I was wondering...when a wrx or some other import drive down the street...i here a loud sucking sound when(assuming) WHEN THE SHIFT GEARS??? is that a super charger??
Cold Air Intakes can be kinda loud, but you are probably referring to a Turbo, as is the case with a WRX. The turbo sucks in air (kinda a whistling sound) while accelerating, and a PSHHHH sound when it "blows off" the air pressure when shifting.
He's right. My intake makes some noise, but I doubt you could even hear it from outside the car. It's probably a turbo kit, which makes a much more noticeable sound. The actual part of the kit that causes the sound is called the blowoff valve. It keeps the turbo from generating more psi than it's supposed to so as to keep it from blowing out.
