You wouldn't need to change the master twice. If you're going with 13 inch rotors up front then you can ditch the power booster and just run manual. You should be able to use a 15/16 inch master from Doctor Diff for 4 wheel disc brakes. You shouldn't need a prop valve with that setup so just a simple distribution block will work. If you want to keep the factory brake light then you'll need a distribution block with the switch in it. Which 13 inch setup are you going to use up front? I just got the 13 inch Viper setup installed on my Duster. That same kit should bolt on your car. I also have the Explorer setup in the rear.