Slamming a car usually affects the handling negatively, so its good that you don't want to slam it.

I would recommend getting some different springs with a higher spring rate and turning up the dampening on the Tokicos. I can't even find the spring rate of your springs on Suspension Technique's own website, so it is probably a good idea to upgrade to something better. A decent set of front/rear sway bars might help as well.

I can't really help much more other than that without knowing exactly what is going on. How does it handle at the limit? What does it do at high speeds that you don't like? How would you like it to handle?