Some helpfull info to remember, the intake air temperature significantly influences the horsepower output of an engine. For example, if an engine's intake temperature was dropped from 110°F to 75°F, then the change is horsepower is approximately +7% ( -1% @ 75°F minus -8% @ 110°F). If the engine normally produces 200 horsepower, then this 7% increase in power translates to about a 14 horsepower increase. Achieving the lowest possible intake temperatures is therefore very advantageous.
ZZP has good links if you look up the wizaired kit on their site. They have boatloads of info supporting the advantage of these kits. I eventually went with the wizaired kit because it was rated number one, and had the data to support its claims.