If you plan on or must use an enamel, use acrylic enamel. It's much better than the synthetic enamel. The next step up would be a urathane single stage. The urathane is much more durable.
Frank Cox Cox Custom Cars
No better smell than that of fresh paint. I've been building and painting cars/trucks for 47 years. Not gonna stop now. http://www.coxcustomcars.com/