Injen Intake sound clip
 

Here's a recording of my Injen intake on my 99 1.6L engine. The sound quality is crappy, but that's because I used one of those handheld voice recorders w/ the small tapes. In real life, it doesn't sound as raspy..more of a deeper sound to it.

http://www.knology.net/~negatize/images/injen.wav

does your intake make a hiss sound after you turn off your car?

Yeah, but it's barely audible unless you're next to the engine. I get this annoying air rushing sound sound if I turn the engine off, then turn the key back to the 'ON' position within a few seconds. Sounds like a rush of air escaping through the intake pipe.