fasteddy,
Lets put some perspective in these engines.
The old engines from the mid to late 30's were developed in circumstances where the 3rd Reich had to be kept content, M-B and Auto Union (Audi) were the racing facade of the 3rd Reich at that time. It was a game of win at any cost to promote the 3rd Reich.
The CART V8 and the subsequent F1 V8 was an Ilmor engine originally funded by Roger Penske with GM backing him up, it then became a Chevrolet engine, and later M-B paid big bucks to put its name on the valve covers of that engine.
The F1 V10 as we all know has not been a spectacular engine, since Mario Ilien left the engine building effort. They are still struggling with their F1 engine program.
DTM engines are probably M-B engines, showing that these engines are sort of the ancestry of the AMG 6.3 is a show of smoke and mirrors.
