tons of debate on this topic. im not 100 percent sure of the size of the master cylinder but changing the proportioning valve is highly recommended. it is the changing of the master cylinder that has more debate. on my 92 hacth i did a disc conversion. at first i didnt change the pro valve and the pedal felt fine. but then again i dont know how much percentage of the braking force was going to each wheel. i did switch the pro valve later on and didnt notice a diffrent pedal feel or braking distance. but then again....i dont know the braking force after the pro valve install. what i am getting to is this....you should be fine for light racing of the streets or whatnopt and daily driving. if track used then i would rec. using all components from the disc setup. master cylinder, pro valve.