I have some Ground Control coilovers, 400# front and 500# rear. I'm using them in conjunction w/Koni yellows.

We just finished readjusting the Konis, and all I can say is the old thing can definitely scoot through some curves.

My car's only 1/2" lower than stock, but there's quite a bit of adjustment in the coilovers to do whatever you need.

Ground Controls coilovers are not expensive, but you will also probably need new shocks of a sporty variety. Bilsteins, Koni yellows, or KYB are all fine.