You have one unused colour on the mirrors, might wanna do something with it.
I think you should go for the more basic areas of light just to get the base right, would be easier to work with later on.
pretty bad edit, but I think it's good enough to help me with my point.
The problem with the hood in my opinion is that it goes from a line which goes to one direction, to a line that goes off to a different direction (as seen in this picture you posted:
http://www.abload.de/img/car_editqcyvf.png)
There's not much you can do about it really, either just make the two lines parallel, or add two colours and bend them (like in my edit), and perhaps add some dithering just to smooth it out.
Additionally, the highlight on the hood doesn't seem too necessary honestly; gives kind of a more blocky look to it, which is what I guess made the impression that the hood is supposed to be flat.
Other then that, it seems to me that some of the highlights don't really have any apparent reason to be where they are, one area I edited which demonstrates that is that piece of metal above the front wheel (no idea what's it called).
I really don't see a reason for the two light reflections to be there, especially when you've got such a nicely placed edge there, where you could just stick any highlight to.
Same would go for the back wheel.
Just out of curiosity, is there a reason you choose to place the light source on the right side, slightly towards the player? Placing the light source from right above the player, overhead, would seem to be ideal; considering you won't have to alter how the animations look when the character goes right or left (or even north-east, north-west, etc.).
