Proper bleeding of the system as well as proper bedding in of the pads is important, but the stock style rotors need better cooling.
Check out my build thread for my solution.
I installed the Touge Factory brake cooling kit which features ducts, hoses, and a proper backing plate that helped tremendously at the track. I can drive 9 or 10/10ths now on track and the brakes are consistent into every corner.
Also get a master cylinder brace, that helps a lot with solidifying the pedal feel in threshold braking situations.