Bought a Japan R manifold that I'll be putting on with the 19T swap and I'm curious if it's worth the time and effort to port out or at least smooth the inlet/outlet port on the R manifold?
I assume the outlet where the turbo mates up to it can be ported to a larger diameter opening as well?
I'm planning on getting it media blasted and powdercoated in a high temp paint before putting it on and I've noticed that the inside surfaces are pretty rough. If the performance gains will be negligible, I won't bother. I'm not aiming for massive power with the upgrade but if there is a decent gain to be made I wouldn't have a problem grinding for a bit on the thing before I take it to my powder coating guy.