It seems to me, and other tech's may have different opinions, but it seems like MOST of the problems were 95 and earlier (124 chassis) SFI cars. The motor was essentially the same when the 104 went into the 210 chassis. I don't know if it took until then before MB made a materials change to the harness or what. Definitely possible it tokk until then, as the cracking insulation definitely took a few years to develop. However I also don't remember doing the harness yet on the SL or C Class with the same motor, for some reason I only remember doing E Class cars. Haven't had one for about 6 months now.
Another minor visual difference I thought of between the CIS-E motors and the SFI motors is the the earlier CIS-E motors also had the wording "MERCEDES-BENZ" on top of the filler panel that covers the spark plugs. I think this was done away with on the SFI motors, instead a star was put on the cover over the very front of the motor, no lettering on the long cover.