Originally Posted by stefan
M3 warranty is only void if participating in competitive (timed) events. You're good to go for the odd HPDE, driving course, autocross (without competing), etc.
The point is, BMW says "track wear is not covered by warranty". And every dealer interprets this their own way. With the Boss 302 LS, Ford and it's dealers would be pissed if you didn't track the car, and they still honor the warranty.