[19bonestock88]

I don't know if the holes will prevent gains, per se, but if you're hypermiling your brake use would be minimal anyway so overheating isn't as big a concern, the brakes still get air from the backside anyway... You need to remember to make the discs a little bigger than your wheel size... I have 15" wheels and cut my discs 16" diameter and in reality you could go even a couple inches bigger...it'll just fill the gap between wheel edge and the bulge in the sidewall