Check out this thread at Fresh Alloy:
http://forums.freshalloy.com/ubbthre...1#Post67739573

Loose valve covers on some cars have triggered this smell.

Weird thing is my G's smell cropped up in November as it was getting colder here in the Northeast, and now it seems to be dissipating as it gets warmer...

BTW, rotten egg smell is from your catalytic converter storing sulfur from the fuel and releasing it as H2S when the cats warm and/or you put your foot on the gas pedal. Either use higher octane gas or try switching brands or change your driving pattern if it bothers you.

 

From what I read on this forum a long time ago, it's a coating on the undercarriage that's used to protect the undercarriage from the salts during the cars voyage from Japan. I had the smell for about the first 8K and then it disappeared. It smells a little like something hot or smoldering under the car after you drive it a bit but then doesn't smell the next time you drive. I've heard its a low temperature oil-based emulsion that's sprayed on the undercarriage and standard driving builds air friction on it which melts the emulsion away. This won't last forever.

'03.5 Silver/Graphite/5AT/4 Dr/Prem/Sprt/Aero/Winter

 

The engine compartment is not sealed well from the fresh air intake at the bottom of the windshield.
That's why the air is always heated a bit when you have it set on vent.

I made the mistake of breaking in the car with the vent on and got sick from the fumes.
It was so bad I had to clean the interior.

I've bought quite a few new cars, and never had this happen before, but this since this is the first one built overseas, the coating Chiphead mentioned must be the cause.

Save your lungs and don't use the vent for the first 200 miles or more.
Use the recirculate only, or hit the off buton.