This is being written to provide some information about using STi control arms on 2009 to 2018 foresters.
modifying your vehicle is inherently dangerous and you assume the risks with this information.
The 2011+ STi aluminum arms are significant because they have a pillowball in rubber for the rear control arm bushing that is less prone to failure, in my experience, than the rear bushing that plagues every subaru in recent years. When I compared geometry of the 2011 arms and my SH steel arm are were identical, there is no gained caster or track width. Additionally, the sway bar mounting ears are the same with as the steel arms. When using the 2011-2014 STi Arm there is the issue of the STI rear bushing not being as spaced down as far as the forester. The factory steel arms spacing with the double sided stud, spacer and bushing is 80mm from the body to the the lower bracket. The 2011-2014 aluminum arm spacing is 70mm, so it is about 10mm too short for the forester. Part 20126FG001 which is the rear spacer from the non lifted subarus double sided stud and happens to be 10mm can be used to make up the difference. For reference the spacer on the forester double sided stud is 20mm.
STi Control arms:
-2008-2010 “GR”, Aluminum and have same rear bushing as found in forester control arms, uses the forester style double sided stud in rear. These arms are not an upgrade in my opinion.
-2011-2014”GR/GV”, Aluminum and have pillowball (heim joint) encapsulated in rubber for rear bushing, spacer on top of pillowball is 10mm short of what is needed for the forester, 20126FG001 is the 10mm rear spacer from the non lifted subarus double sided stud and can be used to make up the difference to use these arms.
-2015+ “VA” , Aluminum and have pillowball (heim joint) encapsulated in rubber for rear bushing, spacer on top of pillowball is 10mm longer than the 11-14 STi arms and is correct spacing forester making it a direct fit. The 2015+ WRX share the same front control arm with the STI., It is safe to assume this fitment will carry through until the STi/WRX move to a new platform, AKA body code, at which time we would have to verify fitment.
There is NO information that I have found suggesting that there is a harder rubber variant for the 2011+ rear bushing, a "group N" bushing if you will.
Rear Bushing Bolt:
901000377, The rear long bolt to replace the double sided stud
Forester Platforms:
-SH 2009- 2013, No know issues at this time with fitment of 2011+
-SJ 2014 - 2018, One member noted they "Needed to trim/remove 2 small metal panels as the STI LCAs are larger and will get in the way". Another member noted that the Arms are shorter width than stock SJ arms and caused issue with camber, additionally the swaybar tabs did not align. more information or pictures are needed, proceed at own risk of adapting.
There is no difference between XT(turbo) and non-turbo front control arms for these years
NOTE
I have no idea about 2019 Foresters, but I would be glad to add the information if anyone finds out.
Mevotech aluminum OEM aftermarket control arms PN:CMS80181 and CMS80182 will not work with 09-18 foresters. They are narrower and meant for 05-09 legacys. Additionally, they are not the pillowball style rear, just a solid rubber bushing.
modifying your vehicle is inherently dangerous and you assume the risks with this information.
The 2011+ STi aluminum arms are significant because they have a pillowball in rubber for the rear control arm bushing that is less prone to failure, in my experience, than the rear bushing that plagues every subaru in recent years. When I compared geometry of the 2011 arms and my SH steel arm are were identical, there is no gained caster or track width. Additionally, the sway bar mounting ears are the same with as the steel arms. When using the 2011-2014 STi Arm there is the issue of the STI rear bushing not being as spaced down as far as the forester. The factory steel arms spacing with the double sided stud, spacer and bushing is 80mm from the body to the the lower bracket. The 2011-2014 aluminum arm spacing is 70mm, so it is about 10mm too short for the forester. Part 20126FG001 which is the rear spacer from the non lifted subarus double sided stud and happens to be 10mm can be used to make up the difference. For reference the spacer on the forester double sided stud is 20mm.
STi Control arms:
-2008-2010 “GR”, Aluminum and have same rear bushing as found in forester control arms, uses the forester style double sided stud in rear. These arms are not an upgrade in my opinion.
-2011-2014”GR/GV”, Aluminum and have pillowball (heim joint) encapsulated in rubber for rear bushing, spacer on top of pillowball is 10mm short of what is needed for the forester, 20126FG001 is the 10mm rear spacer from the non lifted subarus double sided stud and can be used to make up the difference to use these arms.
-2015+ “VA” , Aluminum and have pillowball (heim joint) encapsulated in rubber for rear bushing, spacer on top of pillowball is 10mm longer than the 11-14 STi arms and is correct spacing forester making it a direct fit. The 2015+ WRX share the same front control arm with the STI., It is safe to assume this fitment will carry through until the STi/WRX move to a new platform, AKA body code, at which time we would have to verify fitment.
There is NO information that I have found suggesting that there is a harder rubber variant for the 2011+ rear bushing, a "group N" bushing if you will.
Rear Bushing Bolt:
901000377, The rear long bolt to replace the double sided stud
Forester Platforms:
-SH 2009- 2013, No know issues at this time with fitment of 2011+
-SJ 2014 - 2018, One member noted they "Needed to trim/remove 2 small metal panels as the STI LCAs are larger and will get in the way". Another member noted that the Arms are shorter width than stock SJ arms and caused issue with camber, additionally the swaybar tabs did not align. more information or pictures are needed, proceed at own risk of adapting.
There is no difference between XT(turbo) and non-turbo front control arms for these years
NOTE
I have no idea about 2019 Foresters, but I would be glad to add the information if anyone finds out.
Mevotech aluminum OEM aftermarket control arms PN:CMS80181 and CMS80182 will not work with 09-18 foresters. They are narrower and meant for 05-09 legacys. Additionally, they are not the pillowball style rear, just a solid rubber bushing.