Your intake system can suck inmore air than you cold air dealy can deliver. You can take your pick as to which is gonna give a bit more power. All are minimal anyway unless you're traveling 200 MPH.

Ram air forced extra air into your carb by means of velocity/speed of the car so you're only gonna get a boost at higher speed/flow.

A hood scoop will give a ram effect plus its opening can allow some hot air out/cool air in. Unless the incoming fast/cool air is directed into the intake system turbulance and general loss of air will weaken its effectiveness. Just cool air iunder the hood is good though.

If you use a cold air system get your snorkels as low as possible on the car. Keep both ducts sealed up to the air cleaner which is tight to the carb/intake. Cold air may be best since it always produces even at standstill.

While these 3 methods are long used in piston fighter aircraft remember the speed that they normally operate at make these methods really work. They're negligable at best in cars. But every horse does contribute. Remember the more you can lower the underhood temp the better though, and that may not be by any of these ways.