Spring Rate Opinions? Track Set Up

[bmwccr]

Okay-I want some input on spring rates-I am planning on upgrading to the 4100 ASTs with Hyperco springs-am thinking of either 600lb front/700 rear or 650f/750r-Turner recommends 700f/800r for the Group N set up but Bimmerworld said between 500f/600f and 600r/700r respectively

Background-I have a 96 328is that is predominantly a track car-Its driven on the street less than 500 miles per year-trailered to events-I drive and instruct at car club events on road courses all over the NW
I run the TMS non M swaybars, treehouse control arm bushings and delrin/urethane mounts everywhere else. I have had H&R coilovers on the car since I started tracking the car. I run -3 in the front for camber and -1.5 in rear usually-car is corner weighted
I have a custom roll bar that welded into a box at the top of the rear shock mounts-all Turner reinforcement plates have been welded in-subframe, camber arms, etc
Car is 2800lbs-stock aero for now but I will be adding a better front end soon too.-over time I will continue to lighten the car as well-
I have been happy with the H&R set up over the years but the car is slow to transition-has slightly more roll than I want-Overall, handling characterstics are fairly nuetral at most tracks and I don't want to lose that balance
I want the ride height to be around 12.5/13-from center of hub to fender

Any experience out there with ASTs and various spring rates? I know most of us have to compromise between handling and comfort but in my case I can certainly go on the stiff side-however, I am looking for a balanced car that can still be driven on the street occassionally