Think of a factory air intake system as like when you have a cold that clogs up your head and restricts your breathing, then going for a run, it a little difficult. A cold air intake is like amazing medicine that allows your engine to finally breath. This helps especially when racing.
The AAF Cold Air Intake moves the air filter outside of the engine compartment so that cooler air can be sucked into the engine for combustion. Cooler air brings more oxygen (denser air) into the combustion chamber and that means more power. The filters are usually moved to the upper wheel well area or near a fender where there is more access to free flowing, cooler air and less hot air from the engine!