Venom 400 Computer Module

"You don't have to be a master mechanic to get a major horsepower increase from your vehicle. All you need is a half an hour, a set of hand tools, and Python's Venom 400 performance control module. These Venom 400s increase horsepower by 25 percent in the 1,000 to 5,000 rpm range and reduce delay when you mash down your throttle. And because they only kick on during increased engine load, they don't affect fuel economy under normal driving conditions. They'll work with preinstalled performance chips, have an off switch to preserve smog certification when not racing, and require only four electrical connections during installation." advantages/disadvantages from someones who ever owned a computer mod like this before please? it seems very cheap for the gains it suposedly provides. and does this mean there is a switch where you can totally turn it off when not racing or just disguise it????