I suggest these mods:
fuel pump
turbo back exhaust
manual boost controller
boost gauge
air filter

and when you're done, let me tune it to extract the power, the stock tune is horrible. I have a link in my sig that explains the process and software/hardware required. I recently added a video tutorial to make it even easier.

 

yea, thats what I was reading about, I actually watched the video, It allready has a cat-back and intake filter.