srslider said:I think the twin setup would be overkill, it would be cool although you would run into more problems doing that than you would just upgrading to a nice ball bearing setup. The hp increase, all anyone could do estimate. Alot goes into a HP increase :condition of the motor, boost pressure, and many other factors. I've seen RB with a T3/T4 with about 300hp. Most of the increase you would see is if you upped the boost more. Remember when upping boost make sure your A/F mix is good though. Good luck, sorry couldnt be more help.
srslider said:It would be a good setup, and very cost effective. However if you ever wanted more power, such as 450-500 the turbo will prob run out of efficiency (spelling?) before you get to that point.