You can use regular paint. You don't race and you can't reflect enough heat with paint to see any difference in gains. Even if you use heat reflective paint or whatever. Intake manifold temperature also comes from being on top of the engine, not just engine ambient temperature. I used regular body filler primer. High heat red paint, and high heat clear, 3 years ago. Same paint was used on the half covers. And this was taken a month ago.
Is that a 6.1L aluminum intake? If so, you will trap a little more heat than leaving it unpainted but not enough to matter if you don't race.