1. b16 and b18c5 heads are basically the same, c5 head has minor p&p job, different cams, valves, valve springs, lma's, etc.
2. with the high priced headers out there you really pay for what you get. company's like smsp, hytech, dtr, are all proven to make insane amounts of power by themselves.

my ideal NA setup with a b18c1 would be:

bored to 2.0 liters
aftermarket pistons compression around 12:1
p&p the head
balanced bottom end
hytech header and exhaust
toda b cams and valvetrain
ported stock intake manifold and tb
hondata or something along those lines for tuning
and of course a few hours on the dyno

if that doesnt get me 200whp imma be pissed h: