Of my mods, I'd recommend:
1. Great tires and brakes. This will make a HUGE difference, and they probably need to be changed anyway. For pads, talk to Todd @ TCE (forum supporting vendor). If he doesn't have what you want, check out Porterfield. Somewhat expensive, but they're the only race pad I use. (I haven't tried their street stuff, though!)
2. Brace package - just get the whole set from DDM. The price is right, installation was easy, and it's a very dramatic, positive change.
3. Adjustable shocks. The BC coilovers are great, and 95% as good as the stuff that's twice the price. I lowered the car about 1.25" with these. On the street, even the softest shock setting is way better than the stock Bilsteins, and being able to tighten things up for the track is great.
Note that the factory shocks and springs *ARE* coilovers already, which is nice since you don't need a spring compressor to remove and reinstall them. What you get from aftermarket is adjustability, and being able to configure the car for your driving style, be that racing, spirited driving, or wanting to not feel any bumps in the road.
4. Forced Induction. Be careful with this and, if you do go this route, I'd seriously consider a supercharger over a turbo.
5. Cat-back exhaust. You won't get much, if any, of a perf gain out of this on an NA, but a great exhaust just makes the car more fun. I like my Borla, but others have had great success with Solo and Magnaflow.
6. Anything Norm makes.
Good luck!