is it possible to switch my inner door panels, gray, with an all black interior????

 

This would probably be better asked in appearance, but I'll answer it for ya.

It is possible to order the interior from a Cobalt SS and put it in (which is black) or you could even paint it (quite a bit cheaper, but more effort).

 

yes. and i believe there's a "how to" somewhere in the how to section. i would look it up, it seems tedious but not that hard.