Well, I'm indeed one of the persons who owned an M100 powered W111 Coupe, and my comments are out of that experience. Fitting an M100 powerplant into a W110 will be more complicated and expensive than other options such as a 4.5 or 5.6 M117, handling will be worse (unless the whole air set-up is transferred) and not necessarily faster, especially if this is a US M100 version.

All the above said, M100 are unique pieces of art and truely have a lot of torque. If the work is done properly this could be a very nice car. And people on the m100 board would surely help you. But you should post your idea there to see what comments you get.