I was told by a local shop, in order to achieve streetable 350-400whp with a SR setup is running your basic setup which inlcudes:

Sr Redtop swap
Aftermarket DP
Aftermarket Exhaust
Large FMIC
550 Injectors
Aftermarket Fuel Pump
Aftermarket dual electric fans
Boost Controller
(you could also use parts such as aftermarket oil pan for better oil pickup and aftermarker radiator for better cooling)

And simply adding one of HKS Huge Turbos(dont remember the model, but it was around $1200) using the STOCK SR manifold.

I was told it should yield 350+whp with some good tuning maybe using AVC-R, Haltech, etc...