I've done a few versions with my brakes and frankly the pad selection and tire width are the biggest contributors to short braking distances. With street/track pads and stock rotors (330 mm) I had more stopping power than grip. With R-compound tires and street/track pads I had a good balance but still more stopping power than grip. On a high speed track I overheated my pads and for that reason I now have a Stopteck BBK 355mm and ST-40 calipers. After using several types of Dot 4 racing fluid, several different pads, different sizes of rotors and calipers, different sizes of tires, now I can tell you that the biggest advantage to a BBK is cooling. I can beat the snot out of my brakes and not have fade or boil the fluid. Gut check time folks. If I had installed brake ducts the BBK would have been unnecessary. The only advantages to a BBK are:
you need less pedal pressure to stop
you have a much larger heat sink so you may not need brake ducts
could be much lighter than the stock components.
A BBK will result in $3000 worth of drool and unintelligible babbling.

Les