My set up is stock 95 SE springs (the stiffest available to the best of my knowledge) cut down 1 in. frt & 1/4 in. rr with adjustable Koni's. The struts take care of bounce by damping suspension oscillations. I've seen Eibachs and Roush springs and I can tell you defintively that they are softer than my SE springs. They're made as variable rate, so they're soft at initial compression and they stiffen up as they compress further. Linear rate are preferable IMHO. However, different manufacturers have differing ideas on what works best. Yes, I understnd the logic behind variable rate and when you lower more than 1 inch it's almost a necessity to utilize variable rate to maintain some semblence of ride quality. My ride is stiff, no bounce, with a slight positive rake (Koni's on full soft).
