i bet ya my left testicle with 326mm rotors u wouldnt loose brakes!
my engine builder uses r33 callipers on 316mm? rotors on his mustang with about 1300hp from a twin T04s 400 windsor. And he uses like stock GT brakes on the back - 287 or something.
Power produced has nothing to do with braking ability.
As mentioned before, Mallala is VERY hard on brakes. Try it and you'll see. The brakes will work very well, but I could kill them in 10 ior so laps at Mallala with the right tyres