Hi. Just joined this forum. Looking to buy a pre-owned C240 or C320 4Matic sedan for my wife (need 4 wheel drive for the winter months.) Are there any special/specific problems with the 4Matic system. How about with the 240 or 320 models in general. Are any years more problematic than others? I've narrowed down my choices to either the BMW 325 or 330xi or the MB. What would you recommend and why. Appreciate any and all input.