Do not paint!
There is a MAJOR difference between ceramic coating of an intake manifold and simply painting it!
Ceramic is a thermal barrier coating, so regardless of the color, it acts as a BARRIER to thermal soaking of the intake.
Painting it black, sepecially satin or flat, will markedly improve the thermal conductivity of aluminum, especially if the coating is kept thin (dusting it, or below 3mils). This is the next best thing to military-grade anonidizing black, which doubles the thermal transmission of the aluminum!
Stealth Webb's intake, last I checked was a dark gunmetal grey, but I don't know if it was paint or ceramic coating.
I have seen intakes Jet-Hot coated silver, and they look especially nice. Plus, in conjunction with Jet Hotting the exhaust manifold, would allow for a much colder intake charge compared to untreated items.
My intake is 100grit aluminum oxide blasted on top, with ceramic coating white on the underside. Cerammic coating or painting the manifold WHITE will help decrease the transmitted heat from the manifold. It was common practice to ceramic-based paint (I think that stuff is still out there) the upper portion oc the pushrod tubes on VW and Corvair engines. It was applied to keep the hot, head cooling air from transmitting heat to oil flowing down the tubes. It was good for a 15 degree reduction on my 66 Corsa, and about 8 degrees on my VW Bus.
For astetics, you could ceramic-paint the bottom half white, and the top half gloss black, (gloss black does not accept heat as easily as matte or flat black...) thazt way you had the looks, but still retained the most advantageous position of rejecting and blocking the heat from below...
Call me "Mr. Coating"!