What about your budget? If you change the turbo manifolds and replace your piping with after market gear it does help with the air flow and makes a difference in response plus the induction sound is crazy. Downfall is that it can be expensive which is why I asked what your budget is like.
I'm still looking for manifolds which are around the $1,000 mark (someone is selling on the forums for $900 from Tomei). I bought 115mm thick cooler with piping kit for $800 (Greddy cooler and piping - figured if I'm changing the piping I may as well upgrade cooler). Greddy intake kit cost me $1,500.
You may as well change dump pipes since you will be bringing the turbos out anyways.