some engines "hiss" through a c.a.i. and other just don't, my buddies near stock '96 mustang 4.6 sohc hissed so loud through his bbk c.a.i. that you could hear it over the exhaust from across the parking lot. but my '97 camaro 5.7, cammed, and stroked to 383 was near silent, even if you put your ear right by the inlet
my suspicions were throttle body size/shape factored with engine size/cam profile is what determined whether or not it will "hiss" or if it will "groan", or make no sound at all
please god, do not spend a dime in efforts to accomplish something as lame as the "sound" your intake makes, stick to performance, good sounds (exhaust or intake etc.) are a byproduct of that....that's what seperates us from the 1988 primer gray honda civic owners that buy those fart-can mufflers that whine to make their car "sound" like it has a turbo
his mustang had a "louder" intake, but i was almost 3 seconds faster in the quarter mile, intake sound means nothing