When do you think quality started to decline, computers took over sheer mechanics, computer controls replaced formerly highly engineered mechanical pieces, engines didn't rack up as many miles, doors didn't close with as much of a thud, and generally the association of Mercedes with "long term reliability" moved into the association of "expensive toy."

I think Mercedes has been running on it's reputation for a long time. The W115/W123 diesels that racked up so many miles with so many problems created a reputation of engineering and excellence that Mercedes has not made up as of late. They seem to still be running on the W123/W115 reputation.

Personally, I think the nail in the coffin for Mercedes was the introduction of the 190 series. It marked Mercedes as moving more towards a massed produced, less engineered, less reliable, easier to produce vehicle. I think the last REAL Mercedes was the W126 300SD 5 cylinder turbodiesel, and the 300D W123 5 cylinder turbodiesel. I think after that, Mercedes became something different.

You don't sell your audience new cars if their current ones last for 300,000 miles...