So on the surface, topic / practice may seem nutz but since starting the practice we've yet to get one back that was "close enough". From OEM Ford or GM to aftermarket, all have been flawed. Typical problem, taper towards inside of the flywheel with a wave running lengthwise along the outter approx third of the friction surface. If you want your new clutch and flywheel combo to feel perfect from mile one, money well spent. Had the new OEM Ford alum version for my own car done yesterday, was one of the worst to date.