Ceramic coating manifolds is closer to pissing money away than buying decent headers.
You talk about "lame stock" but at the moment, you're describing building something mighty close to that.
Engines internals will gain you nothing on this build unless you're trying to make this mill last forever. Instead, define what you want it to do, and work backwards from there to get it to meet that goal. Internals are more for reliability at a certain power point, and you're far from that.
