I am going to go ahead and disagree with Driver Found here.
Go with the Sway bar for the rear. Its cheap, and very effective.
Maybe then go with the front sway bar from the 9-3SE. Its larger than the rear, so the car will have a hair of understeer again. Again under $150
Next, MP performance should have some affordable front and rear shock tower braces. Again, cheaper than shocks and springs. I am guessing less than the price of springs still.
You may want to install Poly bushings now, or just go right to the shocks and springs.
The VRK stuff, i.e. mainly the rack brace and clamp, should be considered during heavy perf modding.