Technically speaking the stock intake is a Cold Air Intake as it pulls air from the fender.
Theoretically the aftermarket intakes help reduce restriction to the incoming air increasing power. Bigger is better right? CFM demands of the motor apparently mean little or nothing. Supposedly helps with fuel mileage as well but the cfm demands at cruise and part throttle are restricted by the throttle plate, not the intake ?! And if are getting more air in that means more fuel as well so........
Ahhh... just some of my thoughts.
Righto - velocity of the intake charge matters, too! sometimes intakes are larger (thatswhatshesaid). That can result in a slower airspeed for the charge.
Unless the engine is tested - that is, the CFM going into the engine OR (and probably better) air intake temps are logged, there's no way of knowing if a 'performance' part hurt or helped.
I contend the engine will take in all the air it needs; unless an owner knew the engine was rich due to insufficent air intake...course, with today's ECUs able to compensate I doubt a measurable 'rich' status could exist - the puter would just dial-down fuel.
The intake would probably only help at Wide-open-Throttle; and help so far as perhaps cooler than stock intake charge, but not neccisarily - because, as you said, there's a BIG metal trap-door in the throttle body that opens and closes according to the engine's needs.