Speaking from experience, I disagree with some of the suggestions...
I would FIRST do subframes. You'd be surprised as to how much the car flexes and moves (not the suspension).
Then do "sport" springs. Every company makes them Steed,Saleen,BBK, H&R,... I personally recommend the H&R and Eibach of which both are high quality and wont have to deal with the car leaning to one side or sagging after time...
K-braces are ok, but dont really do that much, at least not with stock street tires.
Performance shocks are nice (and a wee bit of investment), but money well spent. Get Bilsteins or Tokikos, NOT Konis, as they are too much for a street car.
Then tires, tires, tires! Nothing is as important as tires. The problem is that the better and more expensive the tire, the faster they wear (srot'a). It costs to play, how much can you afford to play.
Get that far then stop. Beyond this point it gets "exotic" and you are going to talk to companies like Maximum Motorsport or Griggs, or even the Steed 5-link a buddy of mine developed.
Check out my homepage to see what I have done...
