In speaking with Carl years ago, he said "I can count on one hand how many springs I have seen that were worn out and still have 5 fingers". I was looking for a set for my E3 thinking they were an issue and that is what he said.
I know Paul is trying to build a database like that done by the E28 guys (below). It's gonna be real helpful.
Short Spring and Sway Guide
Basic guide to springs and sway bars. The following shows a basic guide to the springs generally available for the E28. Included is the Spring manufacturer, the front spring rate (for comparison purposes only, and estimated in some cases), and the lowering amount for a stock 535i.
1. Stock - 166 lb/in - 0mm drop
2. M-technik, BMW - 193 lb/in - 20mm drop fr/rr
3. Dinan (Stage 1-4, #D100-0417) - ~200-220 lb/in - ~20mm drop fr/rr or 5/8ths to 3/4 in. drop (also Spring Set #D100-0442 - less expensive, for Euro M5/M635)
4. Suspension Technique (#60065)- ~200 lb/in - 20-25mm drop fr/rr
5. Bavarian Autosport - ~200 lb/in - 32mm drop or 1.25 in. drop
6. Alpina - ~200 lb/in - ~20mm drop
7. Hartge - ~220-240 lb/in - 35mm drop
8. Eibach - ~220-240 lb/in - 30mm/35mm drop, or 1.2/1.4 in. drop
9. H&R Springs - ~220-240 lb/in - 32mm drop, or 1.25 in. drop
10. Racing Dynamics - 274 lb/in - 32mm drop, or 1.25 in. drop
I know Paul is trying to build a database like that done by the E28 guys (below). It's gonna be real helpful.
Short Spring and Sway Guide
Basic guide to springs and sway bars. The following shows a basic guide to the springs generally available for the E28. Included is the Spring manufacturer, the front spring rate (for comparison purposes only, and estimated in some cases), and the lowering amount for a stock 535i.
1. Stock - 166 lb/in - 0mm drop
2. M-technik, BMW - 193 lb/in - 20mm drop fr/rr
3. Dinan (Stage 1-4, #D100-0417) - ~200-220 lb/in - ~20mm drop fr/rr or 5/8ths to 3/4 in. drop (also Spring Set #D100-0442 - less expensive, for Euro M5/M635)
4. Suspension Technique (#60065)- ~200 lb/in - 20-25mm drop fr/rr
5. Bavarian Autosport - ~200 lb/in - 32mm drop or 1.25 in. drop
6. Alpina - ~200 lb/in - ~20mm drop
7. Hartge - ~220-240 lb/in - 35mm drop
8. Eibach - ~220-240 lb/in - 30mm/35mm drop, or 1.2/1.4 in. drop
9. H&R Springs - ~220-240 lb/in - 32mm drop, or 1.25 in. drop
10. Racing Dynamics - 274 lb/in - 32mm drop, or 1.25 in. drop