How in the hell does it have a b16 intake manifold on it? Unless whoever had it drilled holes in the manifold itself to make it fit. If the manifold itself is not restricting any flow at the moment, then there is no point of getting a sk2 IM. You wouldn't be able to make any real power from it without supporting mods.

But things to make some power:
Intake
Hytech or RMF replica header
2.5 inch exhaust (mandrel bent)
Camshafts (ie-ITR, sk2, blox, crower, etc.)
High comp valves (all motor)
3 angle valve job
PnP

And after all of the go-fast-goodies you need a really good tune.