Originally Posted by
persondude32
FWIW the C6 S6 rear brakes are 330x22mm, but the C7 S6 rears are 356mm diameter, so that's probably what you have on your S4, B18b1ex. The C6 S6 rear rotors have a slightly different offset than the C6 A6 rear 330x22mm rotors though, so they're not interchangeable. You can also tell the C6 S6 rear brakes are different than what you have because the C6 calipers don't have a fancy big anti-rattle spring with the Audi or S6 logo, only the front calipers on C6 S6 get the fancy rattle spring.