I have a 2013 CL550 4Matic with the AMG wheels, compared to my BMW 335i, this car glides over the road. The BMW would rattle my teeth although it was a blast to drive hard. The CL550 is not a sports car, it is a very comfy limo that goes like hell when you feel like it! Sport mode is a tad stiffer than comfort mode, less body roll is the most significant difference I can perceive. The ride on the BMW was stiff and connected to the road, you could feel every pebble in the road, the CL feels like a jet flying low, smooth, fast, confident. If yours doesn’t feel right, perhaps the pneumatic suspension needs attention. Tire stiffness can effect the ride quality. The factory tires are soft and wonderful but only last 10k miles...mine currently has m+s tires which are stiffer than factory but necessary for driving in snow. The stiffer tires made only a minor difference in ride quality.