GSC Power-Division billet S2 camshafts for the EJ205 WRX Version 5 and 6. These cams are built to suite the high 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. An upgraded single spring kit will do the job under 8000 RPM.