My soon-to-be-published scientific paper has uncovered some startling information about German marques. Towards the end of WWII, some of the foremost Nazi scientists saw that the tide was turning and came up with a new plan for the continuation of the Third Reich.
Using parts of Mengeles' cloning experiments along with conventional science and occult research, they found a way to distil the essence of Hitler's soul and place it into a car. The Reich would be born through stealth, as the drivers of the cars would slowly be possessed by
Der Fuhrer. The majority of scientists on the project went to BMW, others to Mercedes and some to Audi. A very few went to Volkswagen. (It was generally felt that, given Hitler's part in the company's inception, that it would be too obvious should drivers of VWs all start acting like Adolf).
This spread explains the traditional differences in drivers across the 4 marques:
Braindead Moron Wagon: complete and utter Hitlers
Mercedes: utter Hitlers
Audi: Hitlers
VW: occasionally Hitlerish
Obviously, the odd manufacturing fault or strong-willed driver means that not all drivers fall under the influence.
Since the war the different groups have grown apart, and started to develop their own variations on the process - it may be that Audi's engineers have developed a more efficient way to allow the soul-clone to infect the driver in the past few years.
Those that doubt this need look no further than Audi's own slogan, '
Vorsprung durch technik'. They have convinced the world that it means 'progress through technology', but if one breaks down the phrase it shows the truly fiendish plan the Nazi scientists have hatched.
Vorsprung, literally 'that which came from before'
Durch, future perfect 'shall be made dark'
Technik, 'though technology'
So we get 'that which has come before shall be made dark through technology'. A less literal translation would be: 'Our science will wipe you from history'

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(With apologies to any Edugeekers with German cars - you're obviously far too strong-willed to be possessed by Hitler).