GSC Power-Division billet S3 camshafts for the 08+ Subaru STi EJ257 with Dual AVCS. These camshafts are built to suit high horsepower cars with a power range of 750-1000 WHP and a rev range of 4500-9500 RPMs. Specific engine modifications are required to utilize the true potential of these camshafts including a built bottom-end (sleeved or closed deck reccomended), built/ported heads (casting must be clearanced for higher lift), and upgraded valve springs. A standalone ECU or tune with speed density is highly reccomended in order for proper idle characteristics.