Far too many of the 450s are sitting in junk yards, uneconomic to restore due to serious body rust -- there are two locally in the "u-pull-it" yards. Engines appear perfect (no blowby in fuel distributor), one is marked "runs and pulls good" on the windsheild, but you can see through the floor on both.
My German friend says they were rustbuckets in Germany, too. Otherwise, wonderfull cars, but big gas hogs and that rust.......
That said, I've seen some recently that looked fine, so I guess it's just what you trip on.
They aren't luxury cars in the American mode, though -- I don't know if any have electric seats, and power windows and the horrible Chyrsler servo climate control seem to be the limit for accessories.
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!