Very well done. The yellow really stands out and the black wheels give it a sinister look. Great photography too. I like your backgrounds, they add a lot of interest to your build.
You can try Tamiya TS-26 Pure White in the spray can with TS-13 Clear. They're both model friendly lacquers. I've used TS-26 a few times. Doesn't fade and the color won't shift like Testors enamel. You can also decant the TS-26 if you wish to airbrush it. Either way it sprays very nicely.
Very nice, I really like those big Pontiacs, simple is good. Sometimes they make the best models. I've always liked Iris Mist, very unique color and it looks great on your Poncho.