I'm looking for a car that was being designed to compete in rallying, but never went to because it turned out to be uncompetitive against the Audi Quattro. I never said it didn't compete in other racing series.
My sources are various websites on the 190E Cosworth. Mercedes wanted to compete with the 190E in a high-profile racing series to attract buyers, because it was Mercedes' first attempt at the market of small family saloons. They were mostly targeting Opel, Ford and BMW drivers. These brands were very successful in motorsports. Back in those days rallying was the most high-profile motorsport platform for streetcar-derived racing cars. But with the advent of the Audi Quattro everything in rallying changed, and Mercedes knew that the 190E would not be competitive against the Quattro, so they decided to adapt the by then almost finished engine and car to touring car racing. And it excelled there.
That's just fantastic! Never knew this story...