Uprate the ARBs, fit upper and lower front strut braces. Run slightly more negative camber and change the top mounts so you can alter the camber settings. Get rid of the 17's the car will handle much better on 16s or even 15s.
Up the damping at the back, alter spring rates (this requires some experimentation)
I played about a lot with my setup and it's loads, loads better than standard however it's never going to be as good as I want...