Well here is my experience.
All the 102/103 motors have exceptionally high failure of V/G oil seals. Both the problem and the fix are distinct. Anyone in a hot state that works on these cars can probably tell you how much oil you are using by looking at the plugs that come out of a 15k service. Oil usage in the 500mi/qt to 1000/qt range appear all the time and the plugs will be evenly plated with carbon deposits. A car in this situation can be returned to the 2000+mi/qt condition with the simple V/G seal replacement.
The amount of money to be saved on oil isn't the question here. The real problem here is the build up of carbon on valves and most importantly the catalytic convertors.
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician