So I've got the following mods listed below and I'm looking for more power without going to stage 3 and upgrading the turbo and everything else. So what I need to know is from here, what would be the next best mod?

Greddy EVO2 Exhaust
Perrin Lightweight Crank Pulley
Stock Air Box (recently took out an AEM Short Ram)
Cobb Short Throw
Eibach Springs
Helix Up Pipe
Helix High Flow Catted Down Pipe
Yoko AVS ES 100's (225/55WR16's on my factory rims)
Samco Sillicone Hoses (Anscillary and Coolant)
Cobb Access Port (Stage 2)

Thanks

Chris
New Castle, DE

 

Crucial Racing P&P&C'd exhaust manifold(~$250), GM BCS(~$15), & Custom Protune(~$300)

 

all the heat treated exhaust manifolds do is keep the heat from sinking in to the cast iron headers.
Keeping the heat from escaping keeps the molecules moving faster through the headers up to the turbo. It helps a bit with spool up according to a couple friends that have them.

There is not much else you can do. Unless of course you are running this setup with out engine management, which would be bad.

You could also get an alchohol injection kit.

You could get a bigger TMIC to prevent heat soak and decrease lost pressure generated by the turbo.
Otherwise, you should upgrade to a 2.5L block ad get the turbo upgrade.

 

True, but the Port & polish smooths all the cast surfaces so that the flow is much better. No loss of lowend like some headers, but with quite a bit improvement on the topend & for a fraction of the cost of quality coated headers.