From another forum re: the same product:

We were so curious that we actually dyno'd one of these suckers.

10hp net loss across the board. It created more of a restriction than anything. They can create boost only against a static amount of air, and not against an engine drawing air out of a large volume area (like the intake manifold).
Here is my recommendation for anyone thinking about an electric supercharger or electric turbo.... it can work, but you need to learn some math first! You need to learn about the relationships between current, resistance and power. You also need to learn about the CFM air volume requirements of an engine spinning X rpm. Now calculate how much cfm is drawn by an engine. Next calculate the boosted cfm requirements for your target boost of 0.5 or 2 psi, whatever.... Once you have that number, find a fan capable of delivering X cfm at whatever rpm.... Now go find an electric motor big enough (note I'm saying big enough) to deliver that fans necessary rpm and power. Once you have that calculate the total reactive load that will be placed on your vehicles charging system. This translates directly into a power loss to run the fan. You'll find out after you do the math, that you need one hell of a big motor for the fan (much bigger than anyone sells), it draws one heck of a reactive load, you'll need a better charging system, the motor and fan will weight a whole bunch, are too big to fit under your hood, and a few other reality type wake up call things.

The theory is more sound than some think. The math will show the impracticality of it all. If you want to skip the research and just read about it, Car Craft did the math in an article a few years ago. The motor they ended up finding that would work weighed a hundred to two hundred pounds IIRC.

Don't be scammed by people who are only trying to steal your money. There are many, many scams in the automotive enthusiast world, and lots of them are supported by pretty graphs and dyno charts. The fact is that most "independent testing" isn't independent at all, and most of it is pure fabrication. It is done to convince you to part with your money, and that is all.