Here's one thing that floored me. Check out the stock vs ported exhaust manifold:
Stock:
Ported/coated manifold by buschur racing:
(hughes is confident he can reproduce this with some time and a bunch of porting bits)
Anyways, it is obvious that this is definitely worth doing.
(sorry for no more close-up pics here, but the runners are port-matched, opened up a little bit each)