I would get a Hotchkis front sway bar next when you get the funds. It will help out with under steer during corning.
Rusty is right slow is fast and smooth is fast. Once you get the smooth thing down you can move forward with how to apply the brake quickly, evenly and smoothly. My experience far with handling the Z is equivalent to a high end call girl. You can treat me roughly but remember I am a lady!