Stand by for clarification, though the 2011 rules are not out yet, and there are pending changes for the Street Touring classes (ST*)
-CAI and Strut bar will put you into ST (should still be the case even with the re-org looming)
-CAI + Strut bar + DOT Rcomps will put you into DSP
-Remove CAI and strut bar, but add R-comps and you can still run H Stock
Disclaimer on the above line, to run H Stock, you must run 17x7 wheels with an offset that is within 1/4" of the stock SVT wheel offset.
I'm not sure on both your level of competition, and your goals for your autox season. Basically, how competitive do you want to be?
Some additional, unsolicited information:
-The SVT will be very competitive in H stock, especially at the local level
-The SVT will have a hard time keeping up in DSP, against fully prepped cars
-The SVT can do well at a local level in ST
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"