I saw that same infomercial. The product looks enticing, but..

One thing I noticed was that they noted a horsepower increase when the car was approaching 120 mph on the dyno before the addon and 130 after. Think about what they are saying for a minute. According to their own tests, in order to get the increase, the car must be approaching max speed (on most vehicles) or redline on the tach. The average person (myself included) doesn't go above 75 mph most of the time (with the exception of open highway desert driving at 80), nor do I approach redline unless punching it (which doesn't usually last more than 3 or 4 seconds at a time in most cases). Even still, this doesn't come near the speed(mph) they advertise, therefore making any claimed increase non-existent.

Just my observation.