manifold paint & underhood shine ?

[Boog]

I have a set of stock exhaust manifolds to put on and want to smooth them up and apply some paint. I plan to grind them down some but as for the paint I know Eastwood and some others have an exhaust manifold paint. My question is how long can I expect it to stay on. I don't think I want to spend for ceramic coating. This truck will not be a DD.

As for painting inner fenders, radiator support, etc, what do you prefer? Factory semi gloss black with body colored firewall.
Painting most everything under the hood body color.
Or using gloss black on the inner fenders and core support.
Bottomside of hood black or body color.
My truck will be sort of Admiral blue outside and the firewall is already painted gloss met black but I am not opposed to change. I am leaning toward continueing with the met black for inner fenders & core support.