I had a 123 diesel turbo that was a real gem The car had 275,000 when I last saw it, and engine, transmission were A1. I believe the old 3.0 liter diesels are the basis of MB's reputation for longevity. What's more, the turbocharger worked perfectly. Find a turbocharged American car with 275,000 miles.
The new ones are not in my line, I would stil like to have an old 300D Turbo, especially the 5 cylinder version.