As for the 318 with the turbo, this eliminates the head port volume issue. When useing forced induction the port volume doesn't come into play, as much, but you can still have too large of intake port even with a turbo.
It should be better to run a smaller port volume rather than large with a turbo because this will increase you throttle response and torque before the boost is there, then you can tweak manifold pressure(boost) to get the target HP. In general a smaller port head would take more boost to make the same power levels but the larger port head would not make the off idle torque and could be more subject to turbo lag.