There are way too many variables to say which would be better, power is a small part of the autox equation.
In my opinion, a turbo will have greater flexability to put down more power, and be tuned for more area under the power curve in your operating RPM range. Issues like turbo lag can be accounted for with techniques like left foot braking.
But, if you were to run at SCCA events, you'll be put in a class where unlimited wheel and tire options, minimum weights, and high dollar suspension setups will trump an extra 150hp everytime.
If you're not concerned about being competitive, just want to make your SVT fast, and let it loose on the autox course once in a while, I still think turbo is the way to go.
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"