I think the prices have crossed on these cars - the earlier ones, for a good example, have become more valuable than the later ones. A lot of people are thinking as you are. The used car market values practicality and the earlier cars are more practical - because they lack several major problems of the later cars and they are easier to work on for the DIYer. I agree with the earlier post - two things stand out - head gasket oil leak and transmission. It's difficult but good to hear an older car on cold start up. Funny valve train noises are a significant problem. The color of the coolant should be very low on your list, or not on your list. If non-MB coolant is more likely to cause corrosion (and this is a very tenuous proposition) it is still an insignificant issue in the larger picture. I've driven a dozen used Mercedes several hundred thousand miles, have never used MB coolant and have never had any sort of a coolant problem.