There is some work but the wiring consists of post 16. The easy way would be to use the case from a non working MB box that way none of the mods to the car involve cutting wires. Granted, if your system is still working no need to change.

Getting the tach to work / if the signal is used in other parts of the car is the only unknown.

I'm getting the feeling that the MB system is " Capacitive Discharge ". CD has a fast voltage rise time to fire fouled plugs, a slow rise time of a non CD system can allow current to leak across a fouled plug. CD tends to have a very short spark duration, this could cause a miss fire if the fuel air mixture isn't good / combustion chamber poor. However, the short rise time can allow for multiple sparks per ignition event if the system is designed to do so.

CD was pretty much abandoned in the 70's when better electronic ignitions took over and higher voltage was king.