Well POR 15 wasn't what I had in mind. Every other part of the truck that is painted black uses Dupli-Color Acrylic Enamel (DA 1603). My paint guy said that this would be cheaper to spray than what he would have to mix up and be just as good (actually he said any good rattle can enamel, I chose Dupli-Color).
Changing to a different product will end up with a color mismatch that I don't want to deal with.
Although I did use POR 15 on the frame.