As for the M130 engine: We replaced carbs for a 250C M130 with dual DGV some years ago from a commercial source I can not remember. A beautiful baby blue coupe, a rare completely dry example for w114 from the southwest desert, we sold it on ebay - the buyer was a young kid from near atlantic city who was wearing a reversed ballcap and beastie boys t-shirt. Somehow I feel that inexpensive classic is not in as good condition today, but you never know. The long-devalued market for w114 coupes has had an effect on the availability of finding excellent examples - undervalued cars do not survive as well as the more valued SL cars.
Have never heard of 3 carb setups on the M130. The single and dual weber options are so very adequate. This is for engines that had original Solex. Can't think of any sane reason for replacing Bosch mechanical injections as found on the SL and the diesel models. I simply have not experienced a problem with Bosch injection on the SL, the w123 turbo diesel wagon, or a 180D ponton. Not one. As I say this I can not get the SL started, so maybe I am fooling myself?
1967 230SL