After using rattle cans to keep my GTO from rusting more for ten years, it was a HUGE pain to get all the cheap paint off. The only color that lasted any time was yellow, black went to crap, started flaking off, and got chalky after a couple months. Blue metallic looked ok for about 8 months. I will never do that again. That stuff weathers very fast and looks worse than what you have now in no time.
You can get a gallon of Nason tractor/implement enamel for $100, shoot it with a cheap HVLP and get a decent finish that will last a while. It also comes off much easier when you want to do a better job. I painted my street strip car with single stage implement enamel, its the blue one in my avatar. The trick to getting a good shine with that stuff is to thin it 1.5:1 or 2:1 and lay it down in thin coats. You will be happier in the long run than with rattle cans.