is the stock exhaust manifold and downpipe the same as the lsj?

I believe so. Only the '05 + '06 2.2s had the smaller piping.

yeah i was wondering cuz my sis is gonna get a 2.2 cobalt and I figure when I sc my car I would put my intake manifold, the exhaust manifold, down pipe, and cai on her car.

dont believe so

06/07 2.4 and 05/06/07 2.0 share the same Exh Mani and DP -- same part numbers. Not the same as the 2.2

06 2.2 on left, 07 2.0/2.4 on right:

http://cobaltss.net/gallery/files/1/0/2/0/1/exhaust_comparison1_thumb.jpg (http://www.cobaltss.net/gallery/showimage.php?i=35061&c=3)

cool, thanks