here are some spring rates:

Stock 1992 (from FSM)
Front & Rear: 102 lb/in _ _
Front & Rear: 110 lb/in w/ HICAS


Stock 1990 (from FSM):
Front & Rear: 112 lb/in (base)
Front & Rear: 123 lb/in (sports package)


KGMM S21 Sport (Black)
Front: 3.2 kg/mm | 179.2 lb/in
Rear: 2.6 kg/mm | 145.6 lb/in


KGMM S21 SuperSport (Blue)
Front: 4.6 kg/mm | 257.6 lb/in
Rear: 3.8 kg/mm | 212.8 lb/in


KGMM S21 Racing (Silver/Gold)
Front: 6.6 kg/mm | 369.6 lb/in
Rear: 5.2 kg/mm | 291.2 lb/in


Eibach ProKit (Progressive)
Front: 114-200 lb/in | -1.8"
Rear: 114-148 lb/in | 1.6"


Eibach Sportlines (Progressive)
Front: 137-230 lb/in | 2.2"
Rear: 128-200 lb/in | 2.1"


H & R Sport (Progressive)
Front:2.0-2.08kg/mm | 112~116 lbs/in | -1.3"
Rear: 2.5-2.6kg/mm | 140~145 lbs/in | -1.3"

RSR Race Springs
Front: 279 lb/in | 1.4"
Rear: 251 lb/in | 1.2"

RSR Down
Front: 3.0 kg/mm | 167 lbs/in | 1.5" Est.
Rear: 3.0 kg/mm | 167 lbs/in | 1.2" Est.

Tokico
Front: 3.0 kg/mm | 169 lbs/in | -1"
Rear: 2.7 kg/mm | 150 lbs/in | -1"

TANABE GF210 (Grip Feeling)
Front = 2.9 kg/mm | 162 lb/in | -30to -40mm
Rear = 2.7 kg/mm | 151 lb/in | -15 to -25mm

Suspension Techniques: 1.3" drop
Front: 206 lb/in | 1.3"
Rear: 155 lb/in | 1.3"

Tein S.Tech
Front = 3.2 kg/mm | 179 lb/in
Rear = 2.9 kg/mm | 162 lb/in


5Zigen R-Rate (Progressive)
Front = 2.4-5.2 kg/mm | 134-291 lb/in | 1.3"
Rear = 1.9-5.0 kg/mm | 106-280 lb/in | 1.1"


S13 Coilovers


Nismo S-Tune (not height adjustable)
Front: 5.3 kg/mm | 296 lb/in
Rear: 3.9 kg/mm | 218.4 lb/in

Nismo N1
Front: 8/10/12 kg/mm | 448 - 672 lb/in
Rear: 8 kg/mm | 448 lb/in

Tein HA
Front = 6 kg/mm | 336 lb/in
Rear = 5 kg/mm | 280 lb/in

Tein HE
Front = 8 kg/mm | 448 lb/in
Rear = 6 kg/mm | 336 lb/in

Tein RA _
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein RE
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein RS
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein FLEX
Front = 5 kg/mm | 280 lb/in
Rear = 4 kg/mm | 224 lb/in

Zeal Function B-6
Sreet Spec:
Front = 6 kg/mm | 336 lb/in
Rear = 5 kg/mm | 280 lb/in
Circuit Spec:
Front = 8 kg/mm | 448 lb/in
Rear = 7 kg/mm | 392 lb/in


S14 Springs

KGMM DR21
Front = 4.8-3.0 kg/mm | 269-168 lb/in
Rear = 4.0-2.8 kg/mm | 224-157 lb/in

KGMM DR21 Racing (Silver/Gold)
Front = 6.6-3.2 kg/mm | 370-179 lb/in
Rear = 5.2-2.4 kg/mm | 291-134 lb/in

RSR Hard Springs
Front = 5.0 kg/mm | 280 lb/in
Rear = 4.2 kg/mm | 235 lb/in

TANABE SuperH
Front = 3.0 kg/mm | 168 lb/in | -28mm
Rear = 4.0 kg/mm | 224 lb/in | -9mm

TANABE DF210 (Dress Form)
Front = 4.7 kg/mm | 263 lb/in | -30to -40mm
Rear = 4.7 kg/mm | 263 lb/in | -15 to -25mm

TANABE GF210 (Grip Feeling)
Front = 2.8 kg/mm | 157 lb/in | -30to -40mm
Rear = 3.0 kg/mm | 168 lb/in | -15 to -25mm

TRUST Sport Springs
Front = 2.6 kg/mm | 146 lb/in | -25mm
Rear = 2.6 kg/mm | 146 lb/in | -25mm

HKS Super Sports
Front = 4.14 kg/mm | 232 lb/in
Rear = 3.46 kg/mm | 194 lb/in

Tein S.Tech
Front = 4.8 kg/mm | 269 lb/in
Rear = 4.4 kg/mm | 246 lb/in


s14 Coilovers


Apexi N-1 Coilovers
Front = 8 kg/mm | 448 lb/in
Rear = 6 kg/mm | 336 lb/in

Tein HA kg/mm
Front = 6 kg/mm | 336 lb/in
Rear = 5 kg/mm | 280 lb/in

Tein HE
Front = 8 kg/mm | 448 lb/in
Rear = 6 kg/mm | 336 lb/in

Tein RA
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein RE
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein RS
Front = 10 kg/mm | 559 lb/in
Rear = 8 kg/mm | 448 lb/in

Tein FLEX
Front = 6 kg/mm | 336 lb/in
Rear = 5 kg/mm | 280 lb/in

Zeal Function B-6
Sreet Spec:
Front = 6 kg/mm | 336 lb/in
Rear = 4 kg/mm | 224 lb/in
Circuit Spec:
Front = 8 kg/mm | 448 lb/in
Rear = 6 kg/mm | 336 lb/in

S13 coilovers
JIC FLT-A1 (standard rates)
front = 7 kg/mm | 392 lb/in
rear = 5 kg/mm | 336 lb/in

JIC FLT-A2 (standard rates)
front = 7 kg/mm | 392 lb/in
rear = 5 kg/mm | 336 lb/in

both s13/s14 coilovers:
megan streets are 8k/6k 448/336
megan tracks are 12k/10k 672/559

Coilovers for 1995-1998 240SX:

Tanabe Sustec Pro S-OC II
front = 6.0 kg/mm | 336 lb/in
rear = 4.0 kg/mm | 224 lb/in

Tanabe Sustec Pro S-S II
front = 6.0 kg/mm | 336 lb/in
rear = 4.0 kg/mm | 224 lb/in

2/23/06 - assembled all into post. added to faq sticky.