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. Either way, don't claim warranty for brakes/clutch/fluids/tires/etc. But I mean if your engine goes at auto-x or BMW HPDE I'm quite sure that's a warranty item.
By the way, this is the same for the Boss. In fact, your warranty might get shortened if you use TracKey
. I'm not saying it will or won't.. it's really just companies protecting themselves from abuse of their vehicles. There's a right and wrong way to track your car.