I would think that a pair of T3s would be plenty for street pressure, but as those above have said you really need to do some more homework. Not sure how familiar you are with turbo systems, it may be worth it to pick up a book. I bought this one and read it cover to cover....great info in it and serves as a good reference if you need to do some math:

http://www.amazon.com/Street-TurbochargingHP1488-Installation-High-Performance-Turbocharger/dp/1557884889/ref=sr_1_1?ie=UTF8&s=books&qid=1282585571&sr=8-1

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth