I have a 08 G35 Sdn with about 3500 mi. on it right now..
Been very happy with the car other than some annoying rattles in the interior which seems normal for this car for some reason..

However, about the month ago I started hearing this rattle from the exhaust area (muffler) whenever the I accelerate hard exactly at the point where the gear shifts for like half a second.. it's not a very loud rattle but I can definitely hear it.. especially w/ the windows down..

I think something might be loose in the exhaust that might be causing this rattle.

Just wanted to confirm if anyone else has experienced this problem.
Any advise would be appreciated.. thanks!

I have the same issue only when cold.

Its okay, i am swapping it for a STILLEN.

There are quite a few threads on this - there's rattle common to the '07 models that produces a rattle during shifts, usually hard shifts. It's been described as a rattle, a "whoosh", and other things - don't think anyone has diagnosed it, other than most of us thinking it's a heat shield of some sort. Not an issue.

same problem but only a few minutes after each start up. can't tell so much with the windows up, but can definitely hear it with the windows down. a-nnoy-ing.

Glad to hear that I am not the only one experiencing this annoying rattle..
Did anyone take it to the dealer to have this issue addressed and to have it fixed?

Last time I took my car in to fix this, service technician told me that he didn't hear anything out of the ordinary.. IMO I felt like he just didn't wanna take the time and the effort to fix this problem..

my service guy said the same thing, but to his credit, the rattle only occurs a few minutes at start-up after an extended period of time being shut down. my dealership is 20 minutes away, so my ride was nice and warm when i showed up. i didn't want to leave my ride there for 3-4 hours to 'cool down', so i guess i'll have to live with it.