All show and no (slow) ?
http://www.bimmerfest.com/forums/sho...d.php?t=322342
Isn't the PB upgrade based on the 135i brakes? Multi piston fixed calipers? If you are going to track your car, the performance brake kit can be quite dangerous.
Specifically, see
http://www.bimmerfest.com/forums/sho...15&postcount=6