Again, dimlight comes in with a post that probably won't help. I don't know any numbers but what we did on the Chickenhawk was to remove one leaf from each rear spring. Our thinking was to soften the rear and get more weight transfer for acceleration. The car still handled like a rollerskate, but that was probably due to the fact that it was so low it bottomed out the axle on the frame pretty quickly. At that point, there was no more body roll. I guess thats also how I got away with no sway bars. A bit noisy, but effective.