Originally Posted by AF
A ported and polished GS-R manifold with an oversized TB will probably be more effective than a Skunk2 manifold unless you're running a supercharged motor. My observation is that after market intake manifolds are too big and you lose velocity.
In that article I posted, it states that the TB should be proportional to plenum size, so an oversized throttle body on a stock GSR manifold with its tiny plenum will probably not help too much. I still really don't think that the GSR manifold will flow enough for higher lift cams at higher rpms regardless of whether it is ported and polished or not.