I've got geeky tendencies, so I'd love to see an Oxford English Dictionary styled citation list done up in chronological order so that we could determine when the term took hold to mean the very specific thing it means as related to automotive design.
The only problem is the arduous time involvement and access to a comprehensive library of motoring magazines! LOL
Motorsport has an awesome archive but you can only fully view a few before a pop-up pops up and requests patronage in the form of cold hard cash...
www.motorsportmagazine.com
...so I restricted myself to google search result snippets and compiled a short list.
Earlier usage of the term was sort of shorthand for a stereotypical archetype of the German persona in the sense of cold logic and intense meticulousness.
Motorsport has always been a bit dry though as far as British car mags go, other UK publications would usually exhibit much more flair in their writing.
1931
"...according to a German competitor whose passenger counted them with true Teutonic thoroughness) included seventy-six hairpin bends."
1934
"With typical Teutonic thoroughness a school for young drivers has been started at the Nurburg Ring. They are given a chance to show their..."
1936
"By OUR CONTINENTAL CORRESPONDENT Teutonic Thoroughness I wonder how many spectators 'at a Grand Prix realise the immense amount of preparation that has gone..."
1941
"The doctor starts off by complaining that previous standards and comparisons of performance were entirely subjective; and as his tidy Teutonic brain found this very annoying and unsatisfactory, he set about rectifying it with characteristically Teutonic thoroughness."
1952
"The shriek of a Teutonic blower echoed over the Plain that morning as the Druids stirred uneasily in their unterwelt spuken."
1952
"This frame is the work of Prof Dr Ing Eberan von Eberhorst, so, like the Jupiter, the DB3 owes much to Teutonic engineering knowledge."
1953
"... of that unpleasant language and (in my experience) quite alien trend shown by the emphasis laid upon Teutonic things and Germanic ideas."
1957
"...the whole exercise is tackled with that typical Teutonic thoroughness."
1962
"In his book “The Vintage Motor Car,” Mr. Clutton refers to a certain Mercedes as “. . . a typical example of Teutonic brute force.”
1969
"...which were rather stolid and Teutonic but immaculately made, and as a means of establishing the effectiveness of the Mercedes system of..."
1969
"It is on station-wagon lines like a Teutonic version of a Renault 16, with a long, almost vintage snout and a brief, skirted behind."
1980
"He laughed weakly in mock exasperation of the Teutonic mind trying impose perfection upon an unruly but brilliant Gallic principle."
1983
"As an aside, I note that the golf-ball gear-lever knob, rather rough to handle, is retained, a nice touch of Teutonic humour."
1984
"German design is usually described as “typically Teutonic”, yet two of the most striking cars of recent years have come from the pen of an..."
1986
"Bristol followed the Teutonic looking 400 with the 401 which was essentially a styling exercise by Touring of Milan refined and smoothed in..."
1988
"The whole car is 100% Teutonic in every way, which you would expect from a GT car from Unterturkheim. There are many blindly patriotic Brits..."
1990
"...aggressive coupé body, the 2.24v provides Q-car ability with performance figures that make Latin, British and Teutonic supercars flinch."
1990
"Like any other Audi in appearance, it lacks the Teutonic splendour of the Mercedes or the style of the Jaguar. Despite the exploits of the..."
1991
"The controls are more scattered than one would attribute to Teutonic minds, leaving the hazard warning flashers over toward the glove box."
1999
"An exotic Latin sports bolide? A Teutonic limousine? Or some high-tech, megabucks road legal rally car? No. They're talking about the Ford Focus..."
2000
"It wasn't a machine efficient in the Teutonic manner, like the W196, but he loved it because it could be over-driven, allowing artistry in..."
2001
Niki was perceived to be a very mechanical, 71b+ teutonic computer-type of driver which is how he was professionally, because he was able..."
2007
"The spectacle of silver German cars crushing foreign competition was not just a public demonstration of Teutonic engineering superiority but..."