I would probably go with an E30 M42 (1990 or 1991 318i, 1991 318iS) since it has slightly simpler wiring. The E36 ones had the DISA intake manifold& knock sensors which are just more things to wire in. I haven't swapped an M42, so I cannot really give too many tips. I think that there are 2-3 guys here who have put them in E21's though.
You probably don't need to mess with the EDIS conversion. The M42 uses solid-state, coil-per-cylinder ignition. There is no need to do an ignition conversion since it never had a distributor.