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Discussion Starter #1 (Edited)
Alright, If you're reading this, 2 things must be true; You have an SF Forester, and You've lowered it or are thinking of lowering it.

Now then, you may be wondering why did I make this post? Here's what I hope to achieve1 in this thread:

1: Explain and show the differences between the SF Chassis regarding suspension in comparison to the GC and GDA
2: Go over what things need to be changed on the SF chassis to achieve GC/GDA geometry when lowering.
3: List of what's a direct bolt in swap from the imprezas to the SF, PRE and POST spacer removal
4: Partial how to on correcting the foresters factory lift and a parts/price breakdown of each
5: Attempt to keep as much misinformation as possible out of this thread!
Mods, Scooby experts and what have you, If you think/know something in this thread is false PRIVATE MESSAGE ME and we shall discuss what's what, and I shall edit my posts in this thread accordingly.
IF you think you know something I don't, or that I missed; PM Me.

Why? Because If we fail to work together on the above, this thread will turn into a bunch of posts from different people who read different things on different forums, thusly clogging the thread and making the GOOD information harder to find/read.

Alright before I continue, IF YOU OWN/DRIVE an SG, SH or SJ
THIS THREAD DOES NOT PERTAIN TO YOU!
SG people, there's several threads for your chassis like this one, DO NOT USE THIS THREAD AS ANY SORT OF GUIDE/DOES THIS FIT unless you have an SF. I do not have an SG in my possession so I CANNOT confirm or deny how similar or different the two chassis are.

Now that I've gotten that out of the way, let's begin.

You own an SF Forester (1997-2002), which in reality is a hulked out station wagon that came from the factory with a lift kit of sorts.

Now Subaru, being a small company and relatively simple when it comes to engineering decided to design the FORESTER on the GC platform, What that means is, the front half of your Foresters Unibody/chassis started life as a 93-01 IMPREZA, with a few things changed. Things like radiator support, headight frame section, Roof section, A and C pillars and other things. The back half of your FORESTER is very similar to the GDA IMPREZA (MY01/02 JAPAN, MY02/03 USDM) So things like the rear seats, Strut tower mounts, and chassis mount points match closely to the GDA impreza.
So to make this point in layman terms, your forester has GC chassis FRONT END, and a GDA chassis rear end.

Here's the list of what's the same (off the top of my head) and which chassis share said parts
Legend,
MODEL YEAR will be referenced based on USDM standard
GC (all 93-01 AWD imprezas)
GD (All 02-07 Impreza turbo SEDAN NON STI)
* = Includes STI
"" = See exceptions list

  • Front Subframe
    GC Non Turbo (sway bar mount is in slightly higher location)
  • Front Swaybar
    GC Non Turbo
  • Front sway mounts
    GC Non Turbo
    GC Turbo
  • Front Control arms
    GC/GD (Wagon ONLY)
    GC Aluminum (requires STI style endlinks)
  • Ball Joints
    Universal across any 90s-current subaru
  • Front Sway bar drop links
    GC/GD (wagon only)
  • Engine Mounts
    GC/GD (pretty much stayed the same from 93 to now)
  • Transmission Mount
    GC/GD (excludes 6 speed)
  • Transmission Rear xmember
    GC/GD
  • Transmission saddle
    GC/GD
  • Steering rack
    GC/GD"" (05 and up STI rack bolts up, requires longer m10x1.25 60mm bolts for the pinion side mount)
  • Steering knuckle
    93-99 Outback/SUS/GD (GD requires matching the SF steering wheel side, to the GD steering rack side)
  • Front Struts
    GC/GD*(includes MY2004 STI)
  • Front Top hats
    GC/GD (Bolt hole orientation is GC, but GD will fit
  • Steering Knuckle
    GC/GD
  • Inner Tie Rods
    GC GD (STI will fit, but are longer)
  • Outer Tie Rods
    GC/GD
  • Front Hubs/knuckles/spindles
    GC/GD
  • Front Axles
    GC/GD (GD fitment until MY2004.5)
  • Engine Cross Member""
    GC/GD (Turbo x members WILL NOT CLEAR your STOCK exhaust manifold, UEL Headers required to fit Turbo X members) (note GD crossmember requires shimming forward control arm bushings or replacing with the GD bushing)
  • Rear Sway bar
    GC/GD*
  • Rear sway endlinks
    GC/GD* (Lateral links must match endlinks, IE STI LL - STI Endlinks, Stock LL - Non STI endlinks)
  • Lateral Links
    GC/GD* (Note GD STI LLs will increase track width and negative camber)
  • Rear Subframe
    GC/GD* (05-07 STI has solid Subframe mounts)(Note Forester rear subframe has the LL points about half an inch lower to compensate for the lift, parts all fit nonetheless)
  • Rear Knuckles/hubs
    GC/GD""
  • Trailing arms
    GC/GD* (STI is the same, w/upgraded bushings)
  • Trailing arm brackets
    GC/GD*
  • Rear Brakes
    GC/GD"" (excludes 06/07 wrx and 04-07 STI)
  • E brake cables/shoes
    GC/GD""
  • Rear Struts
    GD"" (04 Struts are backwards compatible with 02/03 springs/TH. 02/03 struts REQUIRE SCOOBY SPACER to match with 04-07 springs/TH)
  • Rear Tophats
    GD"" (02/03 are exactly the same, 04-07 DIRECT BOLT ON but must match with 04-07 springs)
  • Rear Springs
    GD"" (Springs must match tophats IE 02/03 TH - 02/03 springs, 04-07 springs with 04-07 tophats)
Boom, I think I've got all the parts in the drivetrain/suspension I can think of.
 

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Discussion Starter #2 (Edited)
Part 2: "I want to put XX or swap XX onto my foz, what parts do I need?" "I want to do XX with my foz or go XX low"

1st things first, if you want your SF5 to handle well and are lowering it more than 2.5" (roughly stock wrx territory) I highly suggest if not require doing the factory lift delete
What does a factory lift delete consist of? Removing every part on the SF5 or modifying them to match up with it's impreza counterparts. This sets the geometry of the suspension to a more ideal place given your vehicles new ride height.

I'm going to bold each part, and put the minimum requirements in red and the suggested way of doing it in black. Part numbers will be in blue
What's required:
Removing the front subframe spacer blocks
You can remove them and place them below the subframe and re tighten the bolts
Replacing the subframe factory metal bolts with shorter more correct ones
20540AA030

Front Subframe
Suggest only: the only difference I can spot, and it's very very hard to tell without putting the two side by side is the height of the front sway bar mounts on the subframe itself is about 3/4 of an inch taller to help OE geometry (note I ran mine with the forester subframe for years without any ill handling from it).

Steering rag joint (aka steering knuckle)
REQUIRED!
When you correct the front geometry you must change out the stock steering knuckle as it will be too long and bind up, Legacy SUS and some outbacks from 93-2002 came with a solid joint that has the same splines as our SF5 but is about an inch shorter which is exactly what you want. GC knuckle will not work! it is several inches too short as the impreza steering column is shorter than the foresters.


front transmission crossmember
Remove the factory 1" spacers on the top of the crossmember by cutting the factory welds and tapping them off with a mallet (this is how I did it)
Replacing the forester forward trans mount with one out of an impreza or legacy manual transmission

front control arm rear bushing housing (AKA tranverse link mount)
Keep stock mount, many anti lift kits made for the impreza chassis replicate the forester and outback transverse mount because it already creates an anti lift effect in order to correct the OE lifted geometry. I personally suggest keeping it and just replacing the awful stock bushings with an aftermarket of your choice
Replace with impreza or GC varient

Drive shaft and Shift linkage
Optional: I recommend doing the shift linkage, especially if you plan on doing a short throw shifter, I did not and the slightly different linkage does move the shift assembly inside the car slightly and may cause issues getting into the rearward gears.
Drive shafts are extremely similar with the center bearing mount being slightly higher in order to keep the shaft in line. (note I haven't experienced issues with this running the stock SF driveshaft)

Rear suspension
Rear sway bar mounts
This one is almost a must, the stock forester mounts are wayyy to tall and put the swaybar at a much less desirable location and you may risk breaking the factory flimsy mounts as well as sway bar end links if you're running a larger bar (20mm and up)

Rear Subframe
Optional, I suggest doing this one if you're willing to put in the effort and plan on going really low.
GC or GD rear subframe will work, the diff mount in the crossmember is different between GD and GC, but the diff bolts into it all the same, the difference will be if you choose to upgrade the bushings you'll need to get the correct part numbers to match GC or GD.

If a part is not listed above, don't worry about it as it most likely if not entirely does not differ from the impreza chassis.

I want to swap in XX into my foz what do I need to do?
04 STI steering rack
You'll need an 04 STI steering rack
custom or L&E fab rag joint for forester (with spacers removed the joint fits tight but works nonetheless)
Factory bushings and bolts fit right up from the forester
02-07 wrx/sti power steering lines??(optional if you're not comfortable bending your factory lines)

05-07 STI Rack or 06/07 wrx rack (they're identical parts except inner tie rods are longer on the STI
obviously you'll need the rack itself, inner tie rods from an 04-07 WRX/STI (threads are thicker where they go into the rack)
Outer tie rods (all the same on subarus from 93-2007 foresters and imprezas
Same steering rag joint as above
2 M10x1.25 60mm bolts
Pinion side rack mount PN: 34166FE050
Bending/adjusting forester power steering lines to fit the new locations, they're not pretty but they do fit and work.

Turbo subframe
using an old Legacy Turbo or GC turbo subframe
Aftermarket UEL exhaust manifold on a nonturbo SF5

Using a GD turbo crossmember (WRX or STI)
Changing out the forward control arm bushings to the longer style, or shimming them with washers
Aftermarket UEL exhaust manifold on a nonturbo SF5
 

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Very cool, I wish this thread was around last year when I was struggling to figure out part compatibility. Steering racks from the GD are also compatible with the SF, including the STi rack. You can even upgrade to an 06+ direct-mount style rack if you also swap crossmembers. The only caveat is that you need to buy a GC-GD steering knuckle, or modify your own like I did. Everything else is bolt-on.

It might also be helpful to note that most GD rear struts and springs will work with a combination of the correct top hats and strut spacers. Struts designed specifically for the wagon are supposed to provide better camber, but pretty much any aftermarket struts are not going to be wagon specific. Sedan struts work just fine, the difference is minimal.
 

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Discussion Starter #6 (Edited)
Very cool, I wish this thread was around last year when I was struggling to figure out part compatibility. Steering racks from the GD are also compatible with the SF, including the STi rack. You can even upgrade to an 06+ direct-mount style rack if you also swap crossmembers. The only caveat is that you need to buy a GC-GD steering knuckle, or modify your own like I did. Everything else is bolt-on.

It might also be helpful to note that most GD rear struts and springs will work with a combination of the correct top hats and strut spacers. Struts designed specifically for the wagon are supposed to provide better camber, but pretty much any aftermarket struts are not going to be wagon specific. Sedan struts work just fine, the difference is minimal.
All correct information.
Definitely haven't finished this thread yet, it'll probably take 2 to 3 weeks given my schedule and how long it takes to type up everything in a concise readable manner using the BBcode.
 

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Thanks man! I'm looking to buy some wrx struts and springs new and according to this it looks like I can use all 4 SF top hats as long as it is 02-03 struts and springs. Very useful
 

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1 year bump for information

:grin2:

[*]Rear Subframe
GC/GD* (05-07 STI has solid Subframe mounts)
GC had same diff mount, but in GD it need dirrerent bushings right?

I got his answer about GD rear. ->

pickup points for the lat links are in different spots , swap in a gd part w/ matching t brace/diff support
If the LL's are in different place. Does that change much suspension geometry with SF arms? Or would adjustable be best option?
 

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Discussion Starter #9
1 year bump for information

:grin2:



GC had same diff mount, but in GD it need dirrerent bushings right?

I got his answer about GD rear. ->



If the LL's are in different place. Does that change much suspension geometry with SF arms? Or would adjustable be best option?
The GC and SF have the same diff mounts, the GD mount is only different in it has a support bar bracket that holds the diff to the subframe instead of directly bolting into the subframe Both should get new bushings due to how horrid the factory ones are.

The lateral links are different between SF and GC, not due the design of the links themselves but because the forester track width is that of a GD sedan. Where as a GC trackwidth is the same as a GD wagon.

The subframe itself that the lateral links bolt up to, are roughly 3/4" difference in mounting hole locations vertically which does slighhtly effect geometry. If you're going to go below 14" fender to Hub, I'd suggest swapping subframes depending on the reasons behind your build.
 

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So I just got some 02 wrx struts, springs, and top hats from a friend with coilovers. If I understand your post correctly, I should be able to just take mine off and bolt these on without replacing top hats or any other parts? My car is a 2000 Forester
 

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I've got a 98 Forester L that I just put 17x7.5 wheels on. It needs 4 new struts as it is, and I'd like to clean up the look by dropping it maybe 2 inches, but I don't wanna slam it--I'd like to keep full turning capability without having to roll the crap outta my fenders... Also, I'm ballin' on a budget, so I was wondering what would be the cheapest route? I should be capable of doing it myself as long as I don't need to press springs...

Should I go with the stock impreza wagon strut/springs on front and back? And if so, what year would work best without me having to refabricate mounts?

Thanks.
 

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Discussion Starter #13
I've got a 98 Forester L that I just put 17x7.5 wheels on. It needs 4 new struts as it is, and I'd like to clean up the look by dropping it maybe 2 inches, but I don't wanna slam it--I'd like to keep full turning capability without having to roll the crap outta my fenders... Also, I'm ballin' on a budget, so I was wondering what would be the cheapest route? I should be capable of doing it myself as long as I don't need to press springs...

Should I go with the stock impreza wagon strut/springs on front and back? And if so, what year would work best without me having to refabricate mounts?

Thanks.
Man I really need to finish this thread.

For your situation, WRX wagon full take offs from 02-07 (struts, springs, and tophats fully assembled) and a 1/4" inch saggy butt spacer
OR
04 STI takeoffs with a half inch saggy butt spacer
 

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If you're putting KYB struts and swift springs on a 99 forester do you need to change the strut boots and tophats. I am thinking about changing around the suspension for as cheap as I can but those add another $260 or so.
 

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02 wrx springs on 98 sf forester

I need some help here. i have a jdm 98 sf with saggy bum and i was thinking of changing the springs on the car. i can get all 4 springs from my friend's 02 wrx also jdm for really cheap. what i would like to know is will the springs fit and if so would i need spacer for the rear and what size?
 

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This thread is great and has cleared up alot of question I had about swapping parts. I'd like to get a suggestion if I may though - Which takeoffs would you you suggest to keep the vehicle drop minimal? I'd like to get it lower, but with it being the wifes dd I don't want to make it too low 0:)
Thanks for the help!
 

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When you guys go to get an alignment after changing out parts do you have it set to the original forester settings or do you have to use the settings for the swapped parts? My 02 foz is sitting on a full 02 wrx wagon suspension. So do I tell the alignment shop to use the forester or wrx settings?
 

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HI guys, I have 2000 Forester L and I just bought some Raceland 02-07 wrx coilovers. They drop 1-4", which if what I've read was correct that would be a minimum on 2" for the Foz. Upon installing I realized the front struts are too short. The sway bar doesn't allow the hub to go high enough to bolt up. Any advice? I went with these coilovers based on another thread that said they bolted up with no modifications on an '01. He posted pictures and it was slammed. It's an old thread from 2014, and he hasn't responded to recent posts this year.

Thanks for any help.
 

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Discussion Starter #20 (Edited)
Man I forgot about this, I'm super stoked it became stickied though.
Currently updating my original post, also going to make a parts list for different types of suspension swaps as well as brakes so it's all in one easy location.
Where do I get my information from? well if you've ever seen my build thread you'd know most of these parts have been changed modified or swapped on my own car a few times over.
updated the original compatibility list.
Started my 2nd list, mod requirements.
 
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