Road conditions are sensed (not exactly sure how) as well as yaw and other body functions. Valving in the struts open and close to soften or stiffen the action based on BCM inputs. Obviously there are moving parts and that is what goes bad and costs so much to replace. The new Magnaride has some type of metalis flakes or something in the fluid to make it magnets. By simply applying current they can change the viscosity in a millisecond to control strut action. No moving parts equal less cost and more reliability.