A couple of suggestions...
Those wheels are just crying out for a black wash to make them look realistic and not no "model car." And your paint looks a bit "crinkly." Don't know if you have ever used a polishing kit, but you might want to check it out. They are basically a set of very fine grit cloths that you use in succession, from coarsest to finest, each successive cloth removing the scratches left by the previous one... and smoothing out the surface of the paint until you get a nice, smooth, glassy shine. Just a suggestion...