That's actually pretty normal for direct injected engines. Last winter I was in a loaner 328i with the new turbo 4 for a while (long story) and those things literally sound like tractors when cold. I actually had to specifically check to make sure it wasn't a diesel before filling up for the first time. Closest far it sounds to is a 1.9 vw tdi! Ours aren't that bad but I wouldn't worry about it.
Sent from an abacus
I have the LE5 (NA) and not the LNF. I didn't think the LE5 was DI, whereas the newer 2.4 L ecotech engine used in newer model GM products is DI. I may be mistaken though. At any rate, it's done it since 2006 and it has had zero issues other than a bad exhaust side solenoid valve. I'm not too worried about it and it doesn't last for more than some seconds.
Which again...I still haven't gone out to start the car. The temp is supposed to drop again starting tonight so I suppose I better start it later!