I think most of us would be aware of how the 6.3 came into being. The story of how 'young' Waxenberger virtually 'cobbled together' the initial car for evaluation by Rudi Uhlenhaut (forgotten his title but he was the one to give the go ahead for production purposes) to demonstrate what could be achieved by dropping the 6.3 engine into an air suspended 300 SEL chassis.
All good reading, and part of the folklore. What you don't always hear and read about, is some of the other 'hidden'...