Nebor is right about the stiffness. I have them on my 87 745T along with upper and lower chassis braces, lowering springs and the 25 mm sway bars. That puppy rides like a truck on rough roads. Interstates where it is nice and smooth and your doing 70 plus mph they are great. I would not recommend a stiff shock on a S90 you will kill the ride. If you want better handling find someone that makes a larger sway bars for your car. It will tighten it up with out ruining the luxury ride.