[WSSix]

I need to know what year the donor car is. It sounds like it is a 88+ car. If that is the case, you only need J55 brake rotor and pad abutment brackets. The caliper wasn't different. I'd recommend a new one anyway just to be safe. Aside from those pieces, the spindle doesn't change. Everything that is different is in the pad abutment bracket. If you;re pre 88, you'll need adapter brackets and modified pad abutment brackets

If you're going to get serious about road racing the car, step up to better brakes. The J55 brakes where on the ZR1 cars. The rear brakes were the same regardless of model so the rears are fine. However, as good as this stuff was there is better now. I say do it right the first time and be done with it. I'd go C5 minimum if not look into a C6 Z51 setup or C5/6 hybrid setup. (My TA is C5/6 hybrid on the front. C5 rotors and C6 Z51 calipers which are stronger than C5 calipers). You could go C6Z06 but that's getting very expensive.

Manual or not, I honestly don't know. I would be talking out my butt if I was to answer. I would say talk to Tobin at Kore3 as he knows brakes. Maybe also contact Wilwood. You may even want to take a look at what Wilwood has to offer for brakes but it won't be cheap.

One thing I can tell you about the C4 master cylinder is that it is very biased towards the front of the car. One of the common mods people do that track these cars is to change the bias spring in the MC so that the rear brakes work more. This helps to prevent the nose drive the C4s are famous for. My solution also in tells changing the suspension but that's not going to help you in this case since you're not a C4. If you go manual, you're going to be changing the MC anyway so this is a mute point.