Koni FSDs
First, I'm a BMW driver - never owned a Mercedes - however, I took a test drive in a C350 with 18 inch wheels and was very impressed with the ride and drive of the car - especially considering the 18 inch wheels. Actually, the first Mercedes that I've been impressed with. If the car had memory seats, I would probably own one by now. Since I have to wait for the memory seats, I decided to upgrade the somewhat harsh Sport suspension on my 2005 BMW 325CI with KONI FSD struts/shocks. All reports on the FSDs have been positive and it makes sense that the C350 may have a similar shock - sure liked the ride/drive of the car. YMMV.