An electric ´supercharger´ is crap. Their site claims that the power will be taken out of the battery and not the alternator.. what a load of BS. How do they think the power got into the battery? Any gains your engine receives from this POS will be taken back 3 fold from the alternator.
A fan is a non-compression device. It´s made to move air through areas of equal pressure, not from a low pressure area to a high pressure area. If you buy one of those, plug it in, and instead of letting it fly, put a peice of cardboard across the back so that you´re blocking air from exiting (simulating boost), it won´t push your hand off of it.. it´ll just spin the air trapped inside really fast creating a low pressure area (kinda like a tornado).. pulling the cardboard in closer... in the wrong direction.
Turbos and superchargers work well because they compress the air as they feed it though.