Every morning or after the car has been sitting for several hours, my exhaust sounds like what you hear in the video. In about 20-30 seconds, it goes away. It's been suggested a manifold might be cracked and as the metal heats up it closes the gap and the sound goes away. I've also read all 3.7's do this (G's, Ms, Zs, etc).

Does YOUR car sound like this in the morning ? Youtube link below...

Well that video's audio perfectly reproduces the difference in engine sound you describe. It sounds like an old diesel at startup.

It could be the closed loop idling to open loop. The A/F ratio is richer at cold start to help the engine warm up, then it leans out. Mine does the same thing:

mine does this. only 65k mi. thought this was normal

I guess it is! It seems to last exactly 30 seconds after starting it. Ok... I'll stop worrying so much. Its just embarassing starting it up and sounding like a beater with an exhaust leak for 30 seconds. lol

My M37 has the same behavior, it sounds a little raspy when first started and will become quiet after 30 seconds or so.

But do you hear the raspiness from under the car, like I do, or just out of the exhaust pipes outback?