If you're really worried about losing efficiency (even though, as said, it probably wouldn't be enought to worry about) why not try some radiator paint?



That way, not only would your heat transfer be unaffected, but the color would be dead on for that radiator look.
http://www.eastwoodco.com/itemdy00.a...1.x=56&I1.y=50

 

Lots of factory intercoolers are painted so it cant hurt that much.