Coil Spring Rates        
  Front Front Rear Rear Front/
  Coil Wheel Wheel Coil Rear
  Rate Rate Rate Rate Differential
Stock setups          
924 120 108 54 19 50%
944 140 126 126 23.5 100%
951 160 144 126 23.5 88%
M030 175 158 175 25.5 111%
Cup   1 410 369 335 30 91%
User setups          
Racer1 210 189 149 24.5 79%
Racer2 210 189 160 25 85%
Racer3 250 225 254 28 113%
Racer4 250 225 292 29 130%
Racer5 260 234 189 26 81%
924b 325 293 292 29 100%
Racer12 325 293 335 30 115%
Racer8 350 315 335 30 106%
Racer7a 350 315 382 31 121%
Racer7b 350 315 382 31 121%
Racer9 400 360 292 29 81%
Racer16a 400 360 335 30 93%
Racer16b 400 360 335 30 93%
Racer16c 400 360 335 30 93%
924a 400 360 335 30 93%
Racer10 410 369 335 30 91%
Racer13 450 405 335 30 83%
Racer14 500 450 335 30 74%
Racer15 550 495 553 34 112%
Racer11 600 540 430 32 80%
Racer27 700 630 430 32 68%
           
Full coil overs        
Racer17 300 270 224 400 83%
Racer6 350 315 308 550 98%
Racer18 400 360 308 550 86%
Racer19 550 495 364 650 74%
Racer 24 600 540 246 440 46%
Racer 26 800 720 224 400 31%
           
Front coil - Rear  Torsion bar with Coil-over shocks              
Coil and Front Front Total Rear Torsion   Rear Coil-over Effective
Torsion Advertized Effective Effective Bar Helper Spring Advertized Rate
Combos Rate Rate Rate Rate Effective Rate Rate Differential
Racer20 250 225 231 175 56 100 103%
Racer 22 400 360 343 175 168 300 95%
Racer 21  2 600 540 358 50 308 550 66%
Racer 22 450 405 304 220 84 150 75%
Racer 23 400 360 287 175 112 200 80%
1 Cup springs are progressive rate springs ~150-450#
2 Turned down torsion bars effectivly eliminating their usefullnes.  (It's a class thing)
Note:  Many things effect the chosen rates.  Weight reduction front or rear, Sway bar rates, Shock
dampening rates and more.  Also, drivers preference and driving style play a big part.