What I'm saying is, improving on that stuff could well give you better improvements than filling holes underneath. I get the new car thing, but maybe that could just be a challenge to design a "better" grille block or sedan boat tail.
Anyway, rock on. If you do wheel covers, I've been wondering how it would look to do what we often do in my field, and just paste a photoshop image of a wheel over a flat disc. Like this, but full size-
I have too much fun with
spinning,
abstract shapes to try it myself.