those electric superchargers do make your car faster...
they take money out of your wallet, thereby making your wallet lighter, which in turn makes you lighter, and since you drive the car, YOU are lighter. If you are lighter, then the car is lighter and therefore less weight to haul around, which makes your car faster
Snake oil. Don't buy it. If you're looking for a real performance part, save up the $ and buy an exhaust or an intake or some pulleys, etc.