The 75 electronic distributor does not have the lower points you need
to make the D-jet work. Thus far I am not convinced that it wouldn't be
possible to make a hybrid distributor by putting the upper works of an
electronic distributor into the earlier D-jet distributor. I don't know
of anyone who has done it though. The 75 164 had such a distributor but it
was a 6 cylinder. I'd bet that there are BMW, Audi or Porsche distributors
that are that way too.

Given the choice between the two, I think maybe D-jet has a slight edge on
performance but that is balanced by the fact that you have K-jet installed
and it is working. The edge would be mostly because the K-jet uses the
plate air velocity sensor which imposes a restriction on the airflow while
the D-jet wide open is truly wide open.
--
George Downs, The "original" Walrus3, Bartlesville, Oklahoma