I don't track my E92 M3 anymore (got an E36 racecar), but never had a problem with rotors. OEM rotors are actually pretty darned good quality already. Occasional judder can be from deposits, as others have noted.
Your pads are more likely to fail under track stresses than your rotors. Pads can melt, split, suddenly chunk, and before you know it you have stopping problems and a 4-figure maintenance repair.
Hawk DTC-70s are awesome pads for our heavy beasts, and they are very kind to the rotors and sustain high heat extremely well. (And you can keep them on the car throughout the season, as long as you don't mind the dying cat sound as you approach every stop on the street. Or swap them just for track weekends.) If the 70s aren't doing it, next step would be a BBK kit to get more volume to absorb all that friction heat. That's what I'd do if I were tracking more than the occasional DE weekend.