Hi Aussie(et al),
There are several options for converting the ignition system to electronic. Many years ago (when I had to work on English stuff as well as MB stuff)we used various versions of the LED systems(Crane,Allison,Luminition)to correct the problems inflicted on those cars by "The Prince of Darkness"(Lucas). The kits tended to be a bit too universal.They came close, but they were never quite right.I prefer(and use)a magnetic-trigger system.
The key is to avoid converting a marginal distributor.The kits will compensate for some wear, but the timing will still be inaccurate if the distributor bushings and springs are worn.
The claims made by most of the manufacturers aren't completely untrue, but they do tend to embellish a bit. For example, one claims that the "computer" senses the needs of each cylinder and sends exactly the right amount of current needed to each cylinder. It's a basic characteristic of "any" ignition system to only produce enough current to overcome the single largest resistance in the circuit. So even a stock ignition system "senses" the needs of each cylinder(from an electrical standpoint).
Multi-spark or "CD" boxes are another area of misleading advertisements. The multiple-sparks are required to prevent plug fouling at low speeds due to the short discharge(firing)duration of capacitors....
Please excuse the "plug", but this is what I do for a living. I rebuild and convert Bosch distributors.Please feel free to contact me privately for more information.
ASE Master Tech
Mercedes Tech 19 Years