All TDs had the self leveling system, it was standard equipment. Mercedes designed the car to haul heavy loads, and of course heavy loads weight down the back end. So when Mercedes came out with the TD in 1978, it came standard with the leveling sys. The turbo engine was introduced on the TDs model year 1981. In '82 they put it on the W123 sedans.

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1999 MB SL500 (110,000 mi)
2004 Volvo V70 2.5T (220,000 mi)
2014 Tesla Model S 85 (136,000 mi)
MBCA member