Nothing has gone wrong with the car so far. I have had it checked at "more frequent than normal" intervals because of its age, and there are no major problems. There are a few minor leaks around the transmission coolant pumps, and a slight oil leak. All niggles are easily fixed for about $300.
Shocks need some attention and the weight of the car probably causes them to wear out prematurely. I am considering upgrading to a more robust shock when it comes time to change them.
I replaced the absolutely ugly US-spec headlight units with the Euro-spec units and the car is much improved in appearance.
The car is built like a rolling vault. Everything feels solid and substantial, and the interior is flawlessly laid out in ergonomics (if a bit austere in the traditional German fashion).
The performance is more than adequate. The comfort level afforded by fully adjustable seats (even the headrests are powered!) on long jaunts makes this a true highway cruiser.
Standard equipment includes dual-mode sunroof, powered driver and passenger seats, leather interior, real wood trim on all doors and center console, power everything.
Expect to spend about $5500 - 6000 for good quality examples.
This car is awesome. A 1991, 300E 2.6 in pristine condition. All panels dent and scratch free, interior is flawless except for some carpet wear between the two rear seats. Mechanicals and electrics all work, but the transmission seems to slip some when in reverse. Black on gray two tone (lower cladding) and all chrome shines like new. But the kicker? 261,000 miles on the odometer and it still runs like new! People give approving nods and comment and simply dont believe it. Gotta get oil changes religiously or the car will go to spoil. I recommend every 3000 miles and no more. NEVER synthetics.