first thing i'd be doing is a 3.45 or 3.7 ratio swap in the rear, if your 2Gs will cover it.
Doesnt give you more kW, but multiplies the **** out of all that torque going to the wheels, which is what you want.
I ran 16.3 @ 82.3 mph in my wagon at WSID with a cat-back 2.5 mandrel exhaust. Then went and bought HM headers $450, installed a nice smooth metal intake pipe (already had it, but $150ish usually) K&N cold air panel filter $80, super 6 intake snorkel $65, and was running a "straight through" Cat (shh, tell no one!) that cost me $50. This was all installed by me, so no labour costs.
Initial "snap" off the line was no better, and with all this in place i ran 16.02 at 85.4mph. So, the gains were there for mid-top end power, but the stock 3.08 ratio was killing me off the line- 6oft times were still in the 2.3 range. I would have run easy mid 15s with a set of 3.7s
For what its worth, i'd go the diff swap firstly, then some extractors and a redback 2.5 exhaust (minus the rear muffler of course), and then later on maybe some Yella Terra 1.8 ratio rockers (which apparently are really good for all over gains!)