Regarding paint, you can get great paint mixed up in great spray cans at most auto paint suppliers. As long as you get the 2-part clear in a can (the same thing you'd use in a gun), then your paint should hold up to gasoline fine. Just make sure to prep correctly. Prepping means removing ALL of the paint with stripper/sanding, filling any dents with bondo, spraying down with a high quality primer, and then completing the paint job according to your local paint shop's advice.
In my opinion, a high quality spray can will give you better results than a cheap spray gun.
C-man