I'm finally getting around to installing my hydroboost unit, but need to clean and paint it first. Anyone know if there is anything inside them that I need to be careful with while doing this? I'm figuring on plugging the ports, then using Simple Green to start, but don't want to mess it up if I have to break out the solvents.

None that can't handle a dunk tank. When I did mine, it was covered in grease and I dropped in the solvent tank and it has always worked fine.