wondering if the s5 tii upper and lower intake manifold are better than s4 ones on a s4 tii block? I wanna put an s5 turbo and manifold on

 

The port size is a little larger on S5 manifolds, but there's not much point if the ports on the block at still S4 sized.

 

Runners are longer, plenum volume is a little bigger I think. No EGR on the s5. I converted to s5 irons with my engine build and then installed s5 manifolds to go with it. I agree that the manifolds are best matched to the irons.