Mark, you have gone to some extraordinary lengths to providing all this vintage information and the great pictures. Whilst not wishing to be negative of your work and also the venerable Classic model the 6.9 can be perceived for, it saddens me to see the 6.9 to be neglected to the extent to which it is by the parent Company. There has obviously been considerable and perhaps evidence as to the sad state of many of these magnificent cars being allowed to degenerate to nothing more than " scrap", and some of that blame needs to be sheathed home to Mercedes Benz in Germany. If one could purchase suspension parts for a "reasonable" price ,it would provide owners with the necessary encouragement to actually save these cars, but the cost is punishing.
Problems were evident even back in 2005 when I attended Mercedes Classic Days in Salzburg. There were hordes of Gullwings, Adenauer Saloons and Coupes, yet I only ever saw one 6.9, and not a solitary 6.3 nor, for that matter, a 600. Maybe the writing was on the wall even then. Sad. Regards Styria