smh
Although I am fairly certain this will be a good track car, it's not suppose to be a track car out of the box. It isn't a GT3. It does many things a true track car can't do. As for your brakes, I'm sure they are fine like all the others have stated.
I have friends running in the A groups using stock E90 M3 brakes for years with just track pads that don't have warped rotors.
After your track session did you keep your brake pedal depressed for an extended period of time and/or use your e-brake?