[johanh13]

If I were to swap in an M3 rear subframe on my e90 335i sedan, which rear toe bar would I need to use? I think the M3 rear toe arm is longer, but is the longer length on the subframe, the kingpin, or combination of both? Anyone know the answer?

[marconi118]

the longer distance comes from the subframe

M3 subframe => M3 arm

[Precision Autosport]

M3 rear control arms are the same length as non-M E90s. They are just stronger, have a higher durometer rubber bushings, and outer spherical joints. You shouldnt have to change anything. The subframe on the M3 is slightly wider, so you will need to make sure your wheel offset will work properly.

[johanh13]

Originally Posted by Precision Autosport

M3 rear control arms are the same length as non-M E90s. They are just stronger, have a higher durometer rubber bushings, and outer spherical joints. You shouldnt have to change anything. The subframe on the M3 is slightly wider, so you will need to make sure your wheel offset will work properly.

Specifically, is the toe arm the same length too? Also, how much wider is the subframe? My car is pre-LCI, I realize the LCI is 8mm wider per side, due to different hubs and carriers... so if I use all my outboard parts, I will be a total of 16mm narrower to begin with. I am planning on installing new wheels; ARC-8 17x9 et30, will that work with stock body on 335i and m3 subframe?

[Precision Autosport]

The rear control arms and rear subframe are the same between LCI and non LCI. The difference in width comes from different hub carriers and hubs.
The rear M3 is about 20mm wider(From my forum searches atleast) then your current suspension. I would highly suggest keeping all of the stock rear M3 control arms, hubs, and shocks. You'll have to make sure you would have proper wheel clearance though. The rear M3 suspension will reduce or even possibly eliminate understeer.
I would however highly suggest upgrading to M3 front control arms and sway bar at the same time however. The front control arms will increase camber and slightly increase the track width. You typically dont want to increase the rear swaybar diameter unless you upgrade the front aswell.

[johanh13]

Originally Posted by Precision Autosport

The rear control arms and rear subframe are the same between LCI and non LCI. The difference in width comes from different hub carriers and hubs.
The rear M3 is about 20mm wider(From my forum searches atleast) then your current suspension. I would highly suggest keeping all of the stock rear M3 control arms, hubs, and shocks. You'll have to make sure you would have proper wheel clearance though. The rear M3 suspension will reduce or even possibly eliminate understeer.
I would however highly suggest upgrading to M3 front control arms and sway bar at the same time however. The front control arms will increase camber and slightly increase the track width. You typically dont want to increase the rear swaybar diameter unless you upgrade the front aswell.

Thanks for the tips!