GSC Power-Division billet S2 camshafts for the 08+ Subaru STi EJ257 with Dual AVCS. These cams are built to suit the higher horsepower Subis. With a power range of 500 WHP and up, you need some certain mods to utilize the true potential of the S2s: built motor, with a built/ported head, and a good engine management system. Upgraded valve springs are required; beehive valve springs are recommended but not required.