since you've already started down the modification road, my standard autocross advice (i.e., don't modify anything for a season) doesn't apply.

Here's what I'd do in your shoes:

-tires and allignment. Falken Azenis are great autocross tires, Kumho 712's and MX's are also decent. As for allignment, I run -2.5 degrees front camber and -1.5 rear, zero toe all around... it works great for me, but if you want a little more rotation, a *little* rear toe out wont hurt. If you don't have a camber kit, you can do it the cheapo way and just lower the car until the camber is right, and then just zero out the toe.

-rear swaybar... I'd reccomend itr just because it has the best results/dollar ratio.

-Revised spring rates.. If you have the "standard" ground control spring rates, they're not very well suited to autocross. Definitely get a lot of time behind the wheel and get a very good grasp of car dynamics before you go arbitrarily picking out spring rates though.

-optional/your preference... Polyurethane suspension bushings. These will do wonders for feedback and control, but are harsh for a daily driver. If you don't intend to get really serious about competition, you may not want to bother. If however, you don't value ride quality too highly, go for it.

-tie bars/strut bars... these do the least of all the things I've mentioned thus far, but they do help. A good last step.