I actually worked that out about 5 minutes after asking but didn't want to look even more stupid!!
I doubt the M110.989 is suitable for COP conversion at all, much (though far from all) of their engine management comes by way of vacuum advance and retard lines on the distributor so to bypass the distributor altogether would mean a less controlled experience and one much less in line with what Mercedes intended the car to run like.
My advice is to keep it all as stock as possible to enjoy the driving characteristics as they were intended to be, as opposed to a patched together attempt at replicating it using different systems.
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