My personal opinion is that it's just a gimmick. Remove the restrictor in your intake hose, you'd have to anyways to install this product and you'll notice a difference.
I checked with the BBB website and checked up on this company about 6 months ago when I first saw their infomercials. They are not in very good standings, a lot of complaints about customers not receiving their money back. A lot of run around if you are displeased with the product, in other words if it doesn't work you'll never see your money!