Electric superchargers do not work! They are as useful as a chocolate tea pot!
Electric superchargers do not work because, the engine's vacuum (the natural suction of air through piston displacement) is more powerful than the push force of the electric fan used on the supercharger. This means the pull of the air from the engine turns the fan quicker than the fan can turn itself due to the fact that there simply isn't enough power to turn the fan at any worthwhile speed. What this does is this puts drag on the air intake while damaging the fan on the supercharger. Hence it breaks fairly easily and leave debris to flow into your intake which may cause engine damage. They're not worth it at all. You'd get better gains from a Cold Air intake.
Don't listen to their LIES!!!