The srt6 coupe spring rates are 451 lb/in front and 480 lb/in rear. Rear spring rate is higher due to lower motion ratio of rear suspension (limited has higher difference 285lbs per inch in the front and 354lbs in rear) . Eibachs are 371 lb/in front and 371 lb/in rear. Eibachs are relying on your progressive bumpstops which are increasing your springrates. Your springrates could be something like 1000+ lb/in in corners. I'm running custom setup - XYZ 30-way adjustable shocks (custom bumpstops) and custom springs with 935 lb/in front and 896 lb/in rear. (used with HR swaybars) Sorry for my English, im from Czech Republic..