I would definatly go with the TPC Turbo system. It is what I am going to be running in my 996 NB 3.8L build. The guys over at TPC are top notch and a a great help. I picked up a GT4094r turbo from them that were going to try out on the TPC kit to see what kind of #'s we get.

http://www.planet-9.com/tpc-turbo-ki...-kit-sale.html
they have the stage1 kit on sale for $6741 but the sale might be over. just call Mike over TPC and see what he can do for you.