What's the difference between the two manifolds? Would an S5 manifold bolt up to an S4? I'm looking into buying an S5 turbo, so I need to know these things as quick as possible

 

The S4 manifold merges the flow from both rotors into one, and has a flap to block off one of the turbo's scrolls at low revs. The S5 manifold is fully divided and does not have the flap.

The turbo and manifold must match each other (i.e. can't put an S5 turbo on an S4 manifold, or vice versa), but other than that the S5 turbo is a direct replacement for the S4 turbo and a good upgrade.

 

So would an S5 manifold bolt up to the S4 engine w/o problems?

 

yes. it's the turbo and manifold that must match.

 

Alright!! Thanks buddy!