A supercharged car is not the same as a Turbo charged one. With the latter you can usually also change the boost pressure via an ecu tune, and that is not the case with this supercharged car. Best effect is to lean the mixture, as they go very rich, but that is also for a reason. Don't go to lean imho, but this is where the gain lies, though not 45 bhp imo. Only a good before and after dyno will show this unfortunately (make sure you also check the A/F ratio, to be sure after the tune you are not to lean).