Spring rate info directly from H&R USA 1-888-827-8881

RSS Club Sport - green springs

Front spring rate 545lbs/in Linear
Rear spring rate 405lbs/in Linear


Sport Coilover - red springs

Front spring rate 469lbs/in Progressive
Rear spring rate 240lbs/in Linear

The reply below explains how each kit works progressively.

 

Here's the skinny according to Joshua at H&R.

The Sport kit - red springs (not PCS) have true progressive rate front springs. The RSS kit have linear rate springs. However, the mini, is a "bumpstop Active Vehicle" due to its small suspension stroke. And so, both kits work progressively. The RSS kit ramps up faster and with a higher rate than the Sport kit.