The S2 cams are designed for those with a GT35R-GT4067 Turbo. No low end power is lost vs the stock cams when used with the larger turbo. The S2 cams will show gains of 50-70whp over the stock cams and in some cases more in the higher RPMS. Great for 2.0L engines revving to 9000rpms or for Stroker motors revving to 8000rpms. The S2 Cams require upgraded valve springs (check out GSC’s Chro-Molly Retainers and single valve spring kit for a perfect upgrade to your valve train). Designed for a rev range of 4000-9000 RPMS(2.0L or 3000-8000 2.2L+), 500-700whp applications. Not suggested for smaller stock appearing turbo setups. S2 cams can run on Factory ECU with custom flashing.