[Mr. 5]

Thanks to various members in this forum, I've tried to gather up the spring rates of OEM and aftermarket springs.

If anyone has anything they would like to add, contact me and I will add the information to this list.

Stock

135i
Front: 120 lb/in
Rear : 350 lb/in

e90 ZSP or e92
Front: 145 lb/in
Rear: 460 lb/in

e90/e92 BMW Performance (Calculated given that the material of this spring is the same as the ZSP springs)
Front: 195 lb/in
Rear: 505 lb/in

M3
Front: 160 lb/in
Rear: 550 lb/in

Aftermarket

KW v1-v3 (non M3)
Front: 190-256 lb/in (progressive average)
Rear: 545-570 lb/in (progressive average)

KW Street Comfort
Front: 286 lb/in
Rear: 572 lb/in

KW Clubsport (non M3)
Front: 400 lb/in
Rear: 570 lb/in

M3 KW v3
Front: 285 lb/in
Rear: 630 lb/in

M3 KW Clubsport
Front: 508 lb/in
Rear: 800 lb/in

Bilstein PSS10
Front: 385 lb/in
Rear: 615 lb/in

Eibach Pro-kit
Front: 148 lb/in
Rear: 456 lb/in

Eibach Multi-Pro-R1
Front: 200 lb/in
Rear: 500 lb/in

Eibach Pro Street S
Front: 134 - 271 lb/in (Progressive)
Rear: 456 lb/in (Linear)

HKS Hypermax
Front: 448 lb/in
Rear: 504 lb/in

Tein Stech
Front: 191 lb/in
Rear: 593 lb/in

Tein Euro Damper System
Front: 280 lb/in
Rear: 392 lb/in

Tein ss-p
Front: 392 lb/in
Rear: 671 lb/in

JIC-Magic Cross
Front: 450 lb/in
Rear: 674 lb/in

TC Kline Coils
Front: 350 lb/in
Rear: 700 lb/in

HP Autowerks Coilover System
Front: Custom Tailored 300-500 lb/in (Contact HP Autowerks)
Rear: Custom Tailored 500-1000 lb/in (Contact HP Autowerks)