YOu dont want to ceramic coat any intercooler piping. Ceramic coating is ment to keep heat inside of an exhaust system. Heat is energry, so if you where to coat your exhaust manifold, you will have more energy to spin the blowdrier.
On any intercooler piping setup, the best material by far is aluminum being that it retains heat the least. Most people make custom aluminum piping out of steel being that its easier to obtain that aluminum bends and is easier to weld by far(my bov is welded on steel). But if you want a really sharp setup, go with aluminum all the way.