If I'm not mistaken, 996 Turbo rotors are either 328mm or 330mm and E46 330 brakes are 325mm. E46 M3 brakes are also 325mm, but 3mm wider.
The brakes on the stock 330 are MASSIVE and are more than up to the task. Why go through all the trouble to introduce more unsprung weight and little to no braking difference??