Now that's a loaded question. Some say, YES, you'll feel the difference, some, NO. It ain't gonna be the "whippin-yer-head-back" type of power increase at all. Hell with as slow of a car as I have, I really don't notice the gains that much. Unless you do EVERYTHING to the engine to make it help the CAI, it won't do THAT much.
And by everything....I mean....Intake, Headers, Exhaust, Throttle body, etc. Just one component of the series of parts won't make a big difference. BUT it is a start.
And as far as sound goes....the engine won't purr like a kitten anymore, but it isn't going to sound like a nice 454 either.
Try searching on
www.sentra.net and
www.nissanperformancemag.com for some more answers.