Not that easy at all to fix that. Next to impossible.
My comments: When doing the wheels, you barely gave them any depth. It looks as if the face of the spokes are paper thin. They just sit there. The are at least 1 inch thick, which you have to show. The inside of the rim of the wheel also has a lot of depth. It should go in a lot more, just enough so that you can barely see through to what is on the other side. Also on the front wheel, you can see all the way through to the front wing. What happened to the rest of the car? That area where you can see through the front wheel should be darkened. You should also add the actual column of the wheel, behind the nut in the middle, where the actual axle is visible, attaching to the back of the rim, essentially driving it. Your technique is very nice, but you really have to work on the wheels. Other than those, it looks really nice.