The 88-92 Mercedes 300 series is a nice meeting point. The design is efficient, elegant and not too complex. The newer models have more stuff that really is not necessary. These years have all that you need for a luxury ride and are still rooted in the old Mercedes tradition of being well overbuilt. The wagon in particular is the best deal because it has the biggest engine, suspension and brakes standard. Also, the long wheelbase gives a big car ride. The 103 engine is turbine like, exremely reliable, and revs nicely for surprising performance. The transmission gives very positive high RPM shifts while remaining very smooth a low speeds. It's also not too big or too small abd u-turns well.
I love the single arm windshiepd wiper. In rain most water channels over the roof. The engine and transmission are a marvel. This car's visibility is excellent. The ride and bump handling are great. The braking is also very good.
The front seat could be more comfortable and have more headroom.