In our market an early '90's 300E or 300CE came with a M103
A 300e 24v or a 300CE 24v came with the M104 with CIS.

The badges on the rear reflected the differences.

The difference at the dealership was how much you payed for the car. You payed a lot more for an extra 12 valves and extra horsepower.

Of course over the years the M103 has been slightly more reliable