Whilst it is getting a bit off topic, the MB models prior to 1986 (introduction of ULP in Oz) did not use EZL ignition and therefore did not have either a fixed or selectable R16 ignition timing programming resistor. They simply used breakerless electronic ignition where the ignition advance curve was determined by the centrifugal and vacuum advance mechanism in the distributor. Obviously without ULP they also did not have catalytic convertors or O2 (lambda) sensor.
From 1986 the ignition system went to EZL which meant the distributor was nothing more than the rotor and cap to send the high voltage to the appropriate spark plugs (and with the introduction of ULP, exhaust catalysts and O2 sensors were added). The timing signal came from the inductive pickup near the flywheel and the advance curve was determined by the EZL module. The R16 programming resistor was a single fixed resistor in some markets (such as AUS and USA) but was the selector as shown above in European markets where the car could be driven through countries with fuels of significantly differing octane ratings. If the selector is marked EZL-KAT it is a catalyst equipped car. If it is marked EZL-RUF or EZL-ECE it is not catalyst equipped. The change to EZL ignition also coincided with the change from purely mechanical K-Jetronic injection to KE-Jetronic which added an ECU to fine tune the fuel mixture.
Sorry for the off topic discussion. It just seemed appropriate to mention it here since since the discussion was heading this way.
107023 - 350SLC: 1973, 3sp auto, icon gold, parchment MBtex (sold July 2012 after 29 years ownership)
107026 - 500SLC: 1981, 4sp auto, thistle green, green velour
124090 - 300TE: 1990, 4sp auto, arctic white, cream-beige MBtex
124090 - 300TE: 1992, 4sp auto, malachite (spruce green), black MBtex
201024 - 190E-2.0: 1985, 5sp manual, black, black MBtex
201028 - 190E-2.3 Sportline: 1990, 5sp manual, arctic white, blue leather
201028 - 190E-2.3: 1992, 4sp auto, blueblack, grey MBtex
201028 - 190E-2.3 Sportline: 1990, 4sp auto, signal red, black cloth (parts car)
201034 - 190E-2.3-16 Cosworth: 1985, 5sp manual, blueblack, black leather
YG2S8 - Mini Clubman GT: 1972, 4sp manual, blue, parchment vinyl (my first car which I still own)