Sorry can't help on the differences. But on the latter question, while inductive reasoning is always suspect, my inductions support the claim that sedans are always powered and wagons always manual. I suppose it has to do with the length of the cable and location problems for the motor in the wagon.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13