Well, I have been driving around all day today, doing my normal routines, and I can again vouch that my car does feel more responsive and has significantly more pep than it did yesterday.
As far as the intake sound, I really don't know what to listen for there. My cars have always made outtake sounds, ie, exhaust. I guess my ear is not trained to listen to my intake.
I will say I heard a slight whirring noise today, but don't know if that is a sound that has always been there that I didn't pick up until today, or if that might be the intake noise you are referring to? And hopefully not my rear diff! I think the noise has always been there though.
Back to a question I posted earlier: If even the slightest bit of plastic shaving debris gets sucked into the engine, do I have anything to worry about? Or will it just get cooked away. How big a piece of something can get sucked into the engine without damage being caused?