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So I have this 2000 Honda Civic 6th Gen that I plan on making specifically tuned for autocross events. But before I go blowing large sums of money on Koni suspension I want to make sure that all the preventative and obvious maintenance for my high miler is taken care of. Below is the start of my list of items I want to get done before I start applying aftermarket parts.

I plan on keeping the car in the Stock H-Street for the remainder of the season, but think over winter I might do a lowering kit and suspension so I'll be moving up a class. I'll take any obvious fixes, and if you have any suggestions beyond the Street class please just let me know so I don't go above my class before I know it.

What I've Done:
-Hankook RS-3 tires on steel wheels
-K&N Air Filter (I've heard I can grind down portions of the airbox to make it smoother, but I'm not sure how much bang I'll get out of that so I haven't wasted my time with it yet.)
-Synthetic Oil (no more cheap stuff for me)
-New brakes all around
-new sparks

What I plan on Doing:
-Replace ball joints
-rear sway bar
-I also need to go through and change all my fluids
-what other tune-up things?

And that's all I really have. Anyone have other suggestions to improve my ride before I start putting on aftermarket stuff?

Thanks.