The C126-generation Mercedes S-Class Coupe of the 1980s is one of designer Bruno Sacco’s undisputed masterpieces, a perfectly proportioned pillar-less coupe that is equal parts elegance, exclusivity, and brash menace. But when it was new, a dozen or so individuals felt that this design lacked a certain quality—specifically, the quality of looking like a flying electric Braun razor.
At...