WOW nice mate!!!
Now i'"m nowhere near your skills but there are a couple of things that will make your render much better(at least i think so:p ).
-I think the car tilts a little to much, sportscars have very rigid suspension.
- Don't know if you did it already but i'm going to say it anyway....Do an ambient oclusion pass and composite the beauty layer and the occlusion layer in photoshop.
- Use depth of field to make the image more real and blend in the contrast between background, foreground and the model.
But other than this minor things you've got a kickass-model:bow: