cracked rear rotors in 10 days on track

Found a crack in the right rear rotor. These are the JHM two piece rotors but it’s probably not their fault. They are 330x22 so pretty small and I was running them on Pagid RS19 pads full time. Does anyone know if the RS7 355mm rear rotors will just drop onto a B8 if I order them from the dealer? Or is it a huge hassle?