Each Paxton supercharging system is designed, tested, and sold to be installed on vehicles in their original or otherwise stock form. We provide the best performance while maintaining a margin of safety that anticipates most driving conditions that the customer may encounter. We certainly could tune more aggressively to add a few extra horsepower, however, we feel that engine reliability/durability would suffer in the long run. Systems are calibrated using California 91 octane pump gas.