Any type of spray paint would work on the surround of your light (I'm with Keith above in using Plasti Dip as you can peel it off if you don't like it or want to go back to original). The gas tank gets more complicated as most spray paints don't hold up to solvents (ie, gas), so if you were to accidentally get gas on the spray paint it would dissolve the paint. You could do a spray paint, and then see if you can find, or order online, SprayMax 2K clear coat to cover the spray paint. That clear coat is more like automotive paint. It's a two part paint that includes a hardener which is resistant to gas. It's probably your best bet if you're not going to use actual automotive paint with a hardener.