Silly question; do you really want to try to redesign the suspension on a W123 to turn it into something else?

It's a 25 year old, 4000 pound, midsize sedan that wasn't designed as a "sports sedan." I have HD shocks on mine with stock suspension, and they handle as intended (with a fair amount of body roll). These are not sports cars and they never will be; if this CD really has 14k original miles, don't screw it up with modifications that the next owner will have to remove.