2k urethane clear coat over oe paint

Just want to make sure it's OK and won't have any bad reactions...

There is always risk with something like that. Your best bet is to use wax and grease remover first and then scuff down the surface with a gray scotchbrite pad or 800 grit sandpaper. Then hit the tank with wax and grease remover again. When spraying the clear be sure to dust on the first few coats very light and dry, with flash off time between coats. If you hose on the clear heavy, solvents in the paint may get under the base paint and start some lifting. Hopefully this will work for you.

Good luck