Muffler Heat

I'm completing my build of a Zenith 750SD with a UL Power 520T engine. The intercooler is close to the muffler and I'd like to keep heat from the muffler away from the intercooler - I'm building a shroud around the intercooler but would like to prevent heat from the muffler a much as possible - I do not want to "wrap" the muffler. Does a ceramic coating work ? Apply on the inside or exterior? Any particular brands? Thx

Years ago I approached my exhaust system manufacturer about ceramic coating. He offered two observations: My warrantee would be voided, and my cabin heat wouldn't wok.
FWIW-