MB-JIM

I would really like to buy a C350 Sport but I want the comfort of a luxury suspension. I have read that replacing the springs and shocks may do the job but has anyone here actually made the modification? If so, what parts were changed and what was the cost?

Sportstick

May I assume you've test driven the C350 Sport and found it too harsh? If so, did you note if the car had 17" or 18" tires? Before going through the costs of suspension modification, I would consider buying the car with 17" wheels and then replacing the tires with Michelin Primacy MVX4 which have one of the highest ride quality and low noise ratings. The change from the original equipment tires will be noticeable, as those use a harder rubber compound to minimize rolling resistance to maximize the fuel economy number which goes on the label. If that change, which you would want to make in any event to maximize ride comfort, is insufficient, it should be possible to replace struts, although I have not investigated that.