Installing Thinner Head Gasket So, my friend and I are thinking of doing this. YES, when I am done with it all, there will be a dyno tune sheet. Don't flip! LOL. But really, should I go about this? I will be talking to my buddy soon about how thin I would like to go. I will keep you guys updated. His friend did did this to his M3, and the power gains were roughly around 40+hp. I don't know the whole story so... keep your bs to yourself. Thanks. Buahaha. Since I will be raising the compression, 93octane will be needed, correct?