gears. None of that other stuff will yield any difference that is worth what they cost.

supercharger would be 2nd. The SOS kits for MY06+ are good for 350-360HP at the wheels

 

but my car is an 2004

 

Gears, or just do intake exhaust mods for sound/looks. Or a used sc kit for the same as all the other bolt ons for some very noticeable gains.

 

Yes, exactly. My kit was less than 2k with a wideband installed by myself.

I was in you position too and there was no way I was gonna spend several thousands for minimal gains and sound.

 

Nothing is worth a crap without a tune, even a stock motor can be retuned and pull a decent bit of power out. Id get something like my setup, berk ceramic coated headers, 70mm tp, and 70mm exhaust. I have skunk2 duals. Get an fipk, less water issues and heat soak means you just have to play with throttle a bit more when you go from a stop. Next big thing is your tune. Get it tuned and thats when you see the improvements. Gearing would be the logical next step if i was staying na, but i want an sc.