I dont want to say use this or that but during suspension development we have found out that ALL Volvo original front springs for FWD 850 and 70-models have the same rate at 1.8 kp/mm or about 100 lbs/inch. This is very soft compared to for example BMW standard springs. The rear springs also show similar results but they are different between body types. (Wagon vs. sedan) The only difference is the height to compensate for different weight or ride height. The shock absorbers have different settings for different markets but many markets only get different ride heights. For example, the C70 T5 with "18 inch" suspension uses the same front spring as 1992 850 GLT in Europe. The partnumber and color marking is the same for both. The C70 T5 uses the same front strut as the V70 R AWD but not the same spring.

Always test drive a car before purchase and if a soft ride is top priority, maybe a Volvo is not what you are looking for after all. Most of the time, tire diameter (not profile height), tire pressure and shock absorber settings are the cause of most complaints. However, the wheelhousings on the 850 dont give much room for larger tire diameters. If you look at the S80 (and maybe the following new Volvo models) the diameter is up 5.6% compared with the 850 and it makes a big difference.