The C-111 (sometimes called C-Trouble-One) while super car fans are disappointed that the body shape wasn't put into production, and rotary engine fans (myself included) were disappointed the RE wasn't put into production, many things we take for granted in the 107, 116 and 123 were successfully tested on the C-111, including:
Zero-offset steering system used in the 116
Turbo Diesel used in the 300SD and 300TD
The enormous padded steering wheel in the 116/123
Bundts first showed up on the C-111
ABS was developed on the C111 and then fine tuned on the 116 ESF cars before being made available on the last of the 116s
Probably other small things I can't remember...
I.