good idea.

 

Remove your back seats and see underneath if the seats foam is melting/burn.
it smell like crap, I don't know if Mitsubishi fix the problem in the 2010/2011 models, I created a post here a year ago or so about it with pictures, and most of the 2008 users discovered the same burn spot after my experience.
First I thought that it happens because my aftermarket exhaust, but it happens also to stock setups.
Look for the post, read it and check your seats, its kind scary but you can fix it with some heat shield material.
I hope mitsu have fixed the issue.
The other strong smell that I always feel is when the oil is near the 3000 miles under hard driving. Or track driving 150 m/h. I have found no leaking in my 2008

 

I'm with everyone else who said it's the lack of recirculate when in defrost mode.

 

Running into that problem now on the S2000. Still smells after two weeks.

 

Only does on defrost for me..I crack a window n it's all good as I drive.