Well, as a disclaimer before spending the money, a well prepped "spec" civic will often beat an SVT in ST. But if you don't often see one, you should be able to do OK in this class.
You didn't mention what tires you're running. Absolutely start there, you should be researching Dunlop star specs, Kumho XS, B-stone RE-11, currently the tires to have this year from what I can tell. If you have the money get some new lighter weight wheels at the same time.
A rear sway bar is the next easy upgrade, a 22mm is a good fit with the SVT set up IMO.
With good tires and a new RSB work on your driving until you are consistant and at the car's limits.
For power upgrades, there is not much worth doing on the SVT for ST. The stock CAT is one of the best OEM CAT's made. Stock intake isn't too bad either.
Parking Lot Hero
2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
"Hella Functional - Raced, Not Hard Parked"