Well, . . .
The first posts were back in February . . . I believe it has now hot market.
Now, on cold air vs/ ram air intakes . . .
They work different.
Cold air ones draw air from a colder location, like the wheel well. The idea is that cold air is denser than warm air, so more combustible air gets into the engine combustion cycle. Thereby, more power is made. The issue on most/most systems (for cars in general), is that the cold air gets to engine ambient temp in the tube, as the tube gets heated. So, the temp itself isn't different, but the overall system is less restrictive than the stock one. So, there are horsepower or torque gains as a result, just for the reason advertised.
Ram air takes in air and shoves it, under pressure, into the intake manifold. So, there is more air coming in, the more power made. This is the same idea, in the form of much higher pressure, of a "blower" (a belt driven supercharger or an exhaust flow driven turbocharger). A ram air version just uses ducting and pressure from forward car movement to add some pressure to the intake flow.
So, the idea of both types is to get more air into the intake manifold, just in a different manner.
Both intake styles can be in a long or short form. A shorter intake has less room in the tubes to heat up the air in them, as there are less tubes and less surface area. Also, a shorter intake should have less restriction than a longer one (less bends and obstructions in the tube to obstruct smooth air flow).
Some "ram air" intakes don't effectively pressurize the air enough to make a "hill of beans" difference, BUT they are short, smooth flowing intakes. So they give more power by a less restrictive intake flow.
What I have learned from a decade dealing with various intakes (and having "power crazy" friends trying to give more horsepower to various year Miata engines, which have less overall systems than most Japanese "hot" cars) . . .
Power is created by various means and an intake design MAY be created by for one technique, but achieve it by another. Also, "Seat of the pants" feel means little on intakes, as sound and location of torque and power can make a power loss SEEM like a gain. Trust dynos, NOT "seat of the pants." Which reminds me, some intakes just MOVE AROUND power and torque, rather than add anything. SO, ultimate horsepower numbers can be improved, mid range power is lost and so is torque across the engine range. Again, dynos tell what actually happens.
Personally, I'd MUCH rather get a system than increases MIDRANGE horsepower and especially torque, as that is where acceleration changes tend to be most effective. Midrange gaining systems may not gain much at higher end or may be an "across the power band" change.
Oh, and I value mid to high TORQUE improvements more than "horsepower." Torque increases usable, real "engine power" more than "horsepower."
