I had the coupling rattle also, replaced coupling, fixed that. The intake noise is hard to describe, whistle, flutter, rattle is only close. If you start the engine with the CAI or the air box disconnected you can really hear the noise. This was how I narrowed down where it was coming from. It went away when the engine was warmed up because less air flows thru the IAC. Got louder when the A/C was turned on because more air goes thru the IAC. Also if you blip the throttle the sound would stop briefly, I figured this was because no air was flowing thru the IAC. I have listened to a few other L67 equipped cars with CAI's, some have less noise than mine on a cold start, some have more.