Done some searching and seem to have mixed results. I am painting out the tub with Raptor but I need to prime it. Issue I have is scratches I believe it needs etch but then you shouldn't etch over paint? What are my choices do I need to spend two days and wire wheel the entire tub, etch and then prime. Or can I just get a litre of primer/surfacer and just prime the bare metal scratches with that? Other question is will I need 2k primer or can I just use single primer/surfacer and then apply the Raptor over that, and not worry about any etch? This is all going on a VR ute which has the factory baked enamel 2 pac.