Built N/A B-series would be a helluva lot more expensive if you want to put down like 190-200 whp.

Turbo B18B or B16A will both give good numbers, with the B16 obviously being a bit more peaky. That's really up to you. Either way you can put down at least 200 to the wheels on the stock internals no problem.

Here's a price run down.

B18B swap with transmission - $1500
RevHard manifold - $475
Turbonetics T3/TO4B 0.63 a/r Stage II turbine, S-3 trim compressor - $875
Tial 35mm wastegate - $250
TurboXS manual boost controller - $75
TurboXS Type-S BOV - $125
RevHard 25" x 8" x 3.5" intercooler - $600
Mandrel-bent intercooler pipes - $200
Assorted hoses, vacuum lines, fittings, clamps, etc - $150
2.75" downpipe w/ flex pipe - $175
3" Carsound hi-flo cat - $90
3" Thermal R&D exhaust - $550
AEM EMS programmable ECU - $1300
RC Engineering 440cc/min injectors - $350 (or DSM 450cc's for less)
B&M Command-flo fuel pressure regulator & guage - $100
Holley (a.k.a. Walbro) 255 lph in-tank fuel pump - $200
ACT HDSS clutch - $450

Alternatively you could call up RevHard and ask em for a Stage 2 kit but say you want to supply your own turbo, wastegate, fuel pump, pressure regulator and downpipe. I don't know if they do custom orders like that or not but it'd get you all your assorted minor parts together in one step, plus the manifold, intercooler, etc. I feel that for the most part the turbos they include are oversized for the intended application, plus they give you a progressive-rate fuel pressure regulator, crappy Deltagate wastegate and not-so-great fuel pump.