Yeah you wont gain, a whole lot, but it will be noticeable. If you wanna be faster then you could always swap the gears out for some 3.73's or 4.10's. That along with those upgrades you mentioned would make for a quick little car.
Cai + Tune + Exhaust is the standard starting point for mods. It's largely considered a 30 hp increase, as said already.
FYI, though, the shorty headers and dual exhaust are going to net you roughly 0 hp beyond what a single axel-back would get you. Certainly no where near enough to justify their price.
I think you would be much better served spending that money on a T-Lok or gears, assuming performance is your goal. I imagine replacing your entire exhaust system with shiny new duals would look nice, though. So if you prefer that, have at it. :bigthumbsup
It does add some. Rake was saying that you could prolly get almost the same increase from a single outlet exhaust upgrade. Depends on your future plans for the car. Duals add a bit of power, make it look better, and sound better IMHO.
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