Powder coating has some really neat colors available including
several aluminum finishes as well as chrome. We have had
aluminum manifolds powder coated with an aluminum finish
with a clear coat overlay (the manifolds were stained and didnt
clean up very well) After running one manifold for a couple of
years, you could see some darkening of the clear coat but it sure
was much better than a bare aluminum manifold that was two
years old.

mike in tucson