I have Ground-Control coil overs my E30 325is. I also have the ajustable spring seats on the rear. Being my first BMW, I had no idea what rate springs to get, so I told Groound Control to send whatever springs they recommend, since they are the expert. Well, after my first season with the car, I have come to the conclusion that the springs are way to stiff. They sent me 550# for the front and 650# rear. What do you guys/gals use, and on what tracks do you use them?