oilchangeguy,
I think that I remember when you purchaces this new Altima but I don't remember the details.
Which engine do you have and what grade PP did you use?
What oil was in there prior to the PP? Was the previous oil FF?
My '04 Altima 2.5 can be a bit, oh let's say, audible! Not noisy so to speak! The engine just isn't one of those engines that are really hushed while idling(but it's not bad!). I once had a 93 Corolla, 94 Accord and my wife's Lexus that were/are really hushed while idling.
My Altima really quiets down on 10W40 in the summer time. Othewise she only gets 5W30/10W30 and I don't really have anymore 10W40. Only used the 10W40 once cause I bought several straggler qts of SynTec, cheap! But the MPG suffered a bit.
I have mixed in a couple qts of 5W20 in the winter with the remainder being 5W30 and you could hear more, including the timing chain while driving til the engine warmed up.
For my 2.5 S, 5W30 seems to be the happy medium of oils, summer/winter, when it comes to quiet(or as quiet as it's going to be) and still have good throttle responce/rev happy with good MPG.
oilchangeguy,
Another thing that I do notice with my particular Altima is...
When I first change the oil/filter, she really quiets down from whatever oil was in there before but then becomes more audible again in just about a month. I'm curious if you will notice this too!