[Stealthee]

Skip the Tstat unless you are having overheating problems. There is no proven power gain from a 180 tstat over stock.

1. Get an aftermarket downpipe. Skip the catback. Stock catback is good to over 350 whp.
2. Pulley size depends on tunability. You don't want to drop pulleys without scanning for KR
3. Skip throttle body spacer. It does nothing.
4. Intake doesn't really help much. It just increases sound. The air is super heated when it is compressed by the supercharger.
5. Either buy your own tuner or find someone local who has one and have them tune your car. A canned tune is never going to be better than an in car.
6. Headers are going to help keep away KR. If you get headers you can skip the downpipe from #1
7. IC starts to help once you start going way smaller on the pulley.
8. Stock injectors are good for a decent amount of power. I don't know that number off the top of my head.
9. Tranny cooler is a must. They are relatively cheap and pretty easy to install. They will help the life of your transmission. You can look into a shift kit while you are at it as well.
10. Rockers, lifters and cam is where you will pick up a lot more power.