I just ceramic coated my 12H-T exhaust manifold and turbo (hot side and elbow dump)...my wastegate I just POR-15'd. I rebuilt my CT-26 with brand new oversized bearing too. WHile you have it off, take a close look at the "flapper" on the hot side of the turbo that the wastegate controls...mine had a crack on the base that I had welded and machined to prevent wastegate leaks.
I wasn't sure if there were any rubber pieces inside the wastegate that might be damaged in the coating process, so I just used POR-15...turned out great anyway. The ceramic coating's main purpose is to insulate heat, and using it like regular pain for the wastegate was not worth the money for myself.
I used the satin type coating for mine in the cast iron gray colour because the satin type finishes withstand heat a lot better than the chrome type.
My 2 cents...