Originally Posted by dachtor
First, the run flats stink. Changing to the Mich SS made a huge difference, and now I'm running square setup so I can more easily rotate and distribute wear. Also, the stainless lines and fluid are a must and are not too expensive. Brakes were mushy after only a few laps before. Now I can run 5+ lap sessions without worrying about the brakes too much. Brakes are honestly one of this cars biggest weaknesses on the track. However, I'm not inclined to make the upgrade on pads/rotors because of warranty and maintenance preservation.
Another huge weakness I haven't addressed yet is the suspension. This car bounces and rolls all over the place and grip/confidence/stability suffers as a result. I will likely make an upgrade to Coilovers, but not the $3500 options. I'm looking at BC racing and there is a local distributor in the Atlanta area that I'm talking to who knows a lot about setting these up. I will say that "learning" what to do with all this body roll has been a good learning experience. I have experienced understeer and oversteer and knowing when you can apply throttle to steer the car is something I'm still learning (and trusting).
I will update again after installing coilovers.
If you're worried about warranty, just swap track pads before/after each event. Stock BMW brakes were not meant to handle repeated heavy braking. I view the ability to avoid fade more of a safety issue than performance.
Sorry but I'll take oem sport suspension over BC any day. And you don't need to splurge $3500, there are many options that price in between BC and JRZ/Motons that are much more trackworthy than BC.