You will not be able to use a 13" Rotor with just PBR GT Calipers, you can use Cobras, Mach1, or Bullitts. You can get a better 3-2 kit from Maximum Motorsports as it is easier to get it to point aft than Matts kit. A rebuilt 93 Cobra Booster is your best bet by far as Brake Booster choice.