yes that is true, mercedes was already far advanced in the development of the w126 successor w10 and had originally planned to debut that by 1988 or match bmw`s 1987 timeline for their entry into the sagment that had previously been owned exclusively by mercedes with its s class. when mercedes learned that bmw had a v12 in the pipeline, and had it definitely confirmed mercedes cancelled what they had planned until then push everything back and went back to the drawing board. so the w140 debuted in 1991. mercedes decidde to develop a v12 not to be outdone by bmw, so bmw bringing a v12 directly had an impact and caused mercedes to do the same. albeit mercedes wanted a more powerful v12 and gave it a full 1000cc more of capacity, resulting in a 400 hp v12 besting the bmw's v12 by 100 hp.
