Originally Posted by Steved
Yes, those are the AP Racing 6-pots as standard fitment on M3 or CSL models. 355mm disc IIRC. I am running it on Pagid RS19s, although some people swear by the newer RS29s.
To give you an idea of how well they brake, I had a passenger riding with me around Donington Park in England, we braked for the hairpin before the main straight and despite wearing a seatbelt, he lifted right out of his seat and remained planted with head against the ceiling until I came off the brakes.
They are such a complete upgrade for the M3 that you would never ask for more. Only the fronts need upgrading too, since the rears are already good enough (provided the pads are upgraded also).
IIRC you were one of the first on BM3W to put AP's on your CSL, and didn't you weigh the old calipers when changing over? Aren't the AP's a lot lighter than the standard BMW parts too, therefore reducing unsprung weight? That and the fact that they look awesome.
Bit off topic, but what's going on with BM3W? (My old sign in was Cslnut).