That's an intercooler in the pic, not sure if it' show too well using your radiator because of how high it sits. We used rustoleum matte black to paint my friends intercooler and had no problems. What I'd suggest is tape paper to the radiator, draw out some GT letters, cut them out and paint em on there using whatever spray paint you'd like, however I would highly suggest you don't use plasti-dip lol.. Good luck with it!
Just A Sixxer!
Proud member of WickedStangs Okc Chapter!