I agree with what you said about not wanting to take on a turbo engine.. I have had several SD cars.. And they do run nice... but the turbo does not last as long as one would like.. also they seem to wear the engines faster.. I have never got more than 250 thousand miles on an SD engine before it was needing a rebuild because of oil use.. However we have a 78 300CD with about 400 thousand that I do not need to add any oil between 3 thousand mile changes.. I have replaced the timing chain and injectors.. and it runs strong..
We live in an area where if my wife wants a good hamburger, run to the mall, or go shopping for material to make some thing.. its a 200 mile trip.. 6 and 7 mile grades at 6 to 11 percent..we run the old 300 up in 3rd grear at 60 mph.. and it often spends lots of time with the throttle wide open...Its my wifes car and has been here thru several SD's..
We did just get another car.. This time a 92 300 CE and are keeping the 300 CD for the winter and short trips.. 500 and less miles so to say..
If I were looking for a commuter I would look long and hard at the 300 D cars.. I do think the 123 cars are about the best built for service.. Also parts are easy to come by... I get most of mine from Mercedes or Performance Products as they put out a great 123 parts cataloge for 123 cars only.. www.************************
I do all my own work and always have... I got my first Mercedes in 1957 and have had lots.. I like the 123 best of all the Cars I have had.. The one I like 2nd best is the 66 250S that I just sold to a friend a while back.. It was show quality as are most of my cars.