Well, how competitive are you wanting to be? And what class are you planning on running?
Reason I ask this, you have some good mods listed, but the brake kit will put you into a non-stock class, something like CSP maybe which is not a good class to run.
I'm not sure on the roll bar situation, I think that will put you out of class as well. You can take the car to the local dealership, or a local mechanic and have him set up a race-alignment for you... Basically, the handling of the car can be greatly improved just by adding a little bit of camber and toe to the car.
But the other mods are fine... K&N airfilter (not full intake!) and a catback exhaust will be about the extent of motor mods that are allowed. A good set of adjustable shocks will be legal, Koni's/Bilstein there are a lot out there that are good... but pricey.
Tires and wheels are good. Many people are swearing by the new Kumho V710 autocross tire, and for good reason. I'm not sure how well they are wearing, but it can't be that bad. This season I've been racing on the new Hoosier road-race compound tire, and it's been awesome. ANd for wheels, a good set of lightweight wheels will be fine, but if nothing else, just get another set of stock wheels and put the tires on there. You can't oversize your wheels in stock class.
And finally, Lightening the car is also a no-no in stock class. You can take out the floormats (big deal) and remove the spare tire and jack. Make sure when you get to an event that you have a 1/4 tank of gas or less... saves a lot of weight as well.
Hope this helps out, these are all the plans I have for my '04 next year. In the coming weeks I need to decide between the Kumho tires and the Hoosiers. I plan on racing at a few Pro-solo events this year, so hopefully I make the right choice. and hopefully the car is competitive!