Thanks for the detailed replied. I have been ruminating on it for a week. I really like the stiff ride of the 335i, so I am a little wary about going to non-RFT’s now. I suppose I could swap out the control arms to make up for it, but that might bump me up a class in AutoX. I am not too sure what that would do to my extended warranty coverage either.
There was a good article in one of BMW auto parts magazines in the past year that covered and entire 335i to M suspension swap. It’s supposed to be pretty easy to interchange those parts. Did you swap out only the control arms,or did you do the sway bars as well?
[quote] The newer BMW non-M suspensions are tuned for the stiffer sidewall run flat tires. They do that by softening up the bushings on the control arms (wishbones and tie rods). Soon after I bought the car I changed from the stock 135i control arms to the M control arms. The ride got noticeably harsher. Then when the RFT were toast, I went to regular tires. The ride returned back to before I swapped out the original control arms. The difference was that the stiffer control arm bushings provided a better feel and less slop in cornering. You would be surprised how soft the stock bushings are to make up for the RFT.
You can use either RFT or regular tires. If you go with regular tires you should get a mobility kit like they have on the M cars (as they have regular tires and do not have a spare).[/quote]