We've been working on all of the cars on your list for years. I know that the clk that you mentioned isn't much of an upgrade from your c class in terms of years, but you can't go wrong with the m112 engine. We don't get too many of those in any more, but for about the last 20 years or so we haven't seen much go wrong with them. IMO, one of the best gas engines that MBZ ever built.