The Full Billet Evo 9 S1 cams are designed for those with a stock turbo all the way to a GT30/50Trim. These cams will not sacrifice any bottom end loss over stock cams; nothing but gains and will promote faster spooling of the upgraded turbos. Gains of 25-40whp (depending on Turbo) have been seen by simply bolting the S1 cams in. Designed for a rev range of 3000-8000rpms, these cams work well on the stock valve springs. 300-450whp camshaft.