Disc Brake donor vs Disc Brake kit....

I don't like the pieced together kits they have, or scarebirds, and ssbc. They are cheaper at first but there is a reason. GM calipers, rotors from whatever newer car "replacements will probably need special machine work to make them match" i.e. centering hole enlargement etc.. special brackets, only made by them, and not able to be purchased individually if one get's bent or somthing. There are some kits that you use the later stuff, but upgrading the calipers to wilwoods. It uses the larger 11" factory rotors. I'm running the factory stuff on my wagon with the small rotors and my car stops great. Even with manual brakes.