A Benz always LOOKS much better than most cars of the same vintage. As you describe this car, frankly, it has not really been that well taken care of. Unless he drives this car STRICTLY on the highway, this oil change interval is not conducive with long engine life.

I'm pretty sure that this particular car has hydraulic lifters so the valve adjustment is not a problem.

I don't think the lack of ATF changes in itself should stop you in your tracks, but I would suggest that you find out what a complete transmission for this car costs and negotiate that amount off the car, then change the ATF and filter as soon as you buy it. This lack of attention is a bad sign though, has the rest of the car been equally neglected.

Another thing that may surprise you is that these motor mounts are pretty expensive. Once you change them, it will make a huge difference in that shaky idle.

Although cosmetically this car sounds nice, don't judge this book by its cover. This car does not warrant paying top dollar for, if you can negotiate the car for a very good price, THEN put it on a much better preventive maintenance diet, you MIGHT be really happy with it.

My $0.02,