Dear peter02910:

A sprint booster electronically simulates an increase in horsepower by decreasing the delay and lag time of a drive by wire throttle body, as our cars have. There is no actualy increase in horsepower.

An ECU reflashing actually optimizes the engine's performance to increase rear wheel horsepower. In our cars' case, it should increase the actual horsepower by 15-25.

I hope this helps, Erik