I'll think you'll find below a most reasonable summary:-
German cars, those who prefer function over form and prefer a miserable interior.
Volvo, Dentists.
Saabs, Architects.
Ford's, people with more money than sense.
BMW, High performing salesmen.
Vauxhalls, Low performing salesmen.
Japanese cars, those that just want to get from A to B.
Italian cars, those who aren't really bothered about getting to B.
Jags, as noted Cads & Bounders.
Bentleys, Footballers.
French car's, The French.
American cars, people who don't do corners, or quality or fuel efficiency or......
Red supercars, men with inferiority complexes esp. in the trouser dept.