Preface: I am compiling information based on questions I have had in my own search. If I am missing anything, please add it or have me add/correct in the top posts. A lot of this information will be pulled directly from other member's posts. If you are updating this thread and have aftermarket wheels, please update the wheel fit thread.
There are a few main options for lowering: Peddlers springs on OEM struts, Swift springs on OEM struts, 09-13 Impreza/WRX struts and springs, and 08-12 STI struts and springs. Most Impreza/WRX coilovers should bolt on directly.
Obviously you can put lowering springs on either the Impreza/STI options, but I'm going with the simple options. If you want the stiffer springs from the WRX and STI but not the drop, Subtle Solutions has multiple width spacers to get you to just about any height. If you are looking at STI or WRX take-off's, read Nollie's WRX strut install
. There are potential issues around the rear upper control arms.
If you are unclear on how to install, ask for help or find a professional. Nollie's install writeup is a great reference tool, but if you aren't sure what you are doing, don't do it!
Peddlers Springs on OEM struts
Drop: 40mm / 1.6"
See Galager's install thread
for more details on these. They need to be imported from the UK distributor.
Swift Springs on OEM struts
Drop: .8" / 20mm
This is going to keep you closest to stock height. New springs are around $300.
Hat tip to jesusv for his pics.
jkoppe has a few good comparison pics below.
Impreza strut assembly
These are bolt-in. No fabrication or spring removal necessary. This is going to be the easiest install.
Mattesonb - hatch struts:
2010subaruforesterXS - 2011 wrx take offs:
STI strut assembly
Fabrication on the front struts is necessary. The rears bolt on directly.
Raptr's install thread: 08 STi Struts on 09 FXT
SH on STI struts and springs
SH on STI struts and springs w/ Subtle 1" spacers (Thanks Subtle for the pics)
WRX After-Market options
GTWORX WRX Bilstein struts with RCE yellows
2010+ Legacy takeoffs
Drop: ~2", but the rear sags
Details: 2013+ has a better/higher dampening rate. The rear sags so recommended a 1" spacer. Needs WRX/Forester tophats.
Shown w/ 1" spacer
This will obviously have different ride height's based on user preference. The ones noted here will be confirmed fit only.
BC Coilovers - Shansen's setup
Cusco Coil options
Other aftermarket spring options
See STIdarkside's post 20
below for his very detailed list of other options.
As I run out of space, post 6
will be updated.