My wife paints lead D&D figures. If you have bare metal, the best thing is to use an etching prep on it. I use Jasco Metal Prep, and it works well. It should work well on the Zamac used in diecast bodies. Properly cleaning and degreasing is also important. Handle the bodies with gloves after you clean them. Definitely use a primer if you're working from bare metal. Other than that, the Tamiya paints, or enamels should work just fine.