If you haven't knocked out the cats ( which I don't think you have yet ) don't do it and sure as hell don't talk about it on a public forum. Fines are big!!!
Your biggest restriction is the dump pipe design. If you want the sound just do the cat back and enjoy. If you want the performance gain go a full 3in turbo back with a good design dump pipe and high flow cats and get it tuned at the same time.
Be warned though with a good 3in
TBE on the standard turbo it MAY spool so well at the track or drags that you can get it to boost cut. I ended up changing turbo's to fix my issue with this as even with the waste gate fully open it would build to much boost.