Automotive paint with a catalyzed curing process. Acrylic enamel most closely approximates the original paint, but there are urethane based single stage paints you can use as well. And you can use most paints as a base coat and then shoot urethane clears over them. Also, some rattle can paints you can find that are fuel proof for RC planes and the like work. And a lot of the guys use that expensive two part paint in rattle cans as well. But no and I mean no, spray paint from a hardware store is going to be fuel proof. They do advertise themselves as "fuel and oil resistant," but so is latex house paint and lipstick. You got my friend Davis right there, and he is an expert at this stuff.