As SweetLeaf said, use radiator paint. I have used this stuff on a radiator and it is a very thin paint, but still has great coverage. Th looks is also a semi-flat look. Good luck.
Also, have you gotten pulled for showing an intercooler? I just couldn't see gestapo pulling you for having a front mount, unless you were boostin' around town like a mad man and they used the intercooler to spot you.