I also had mine tested, but at the time the engine in my 91 300D 2.5 Turbo only had 60,000 km on it. It came in at somewhere between 2 and 3%. It does not have a trap oxidizer and the EGR is partly working (the flap which blocks off part of the clean air intake when the EGR valve opens is disconnected).

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1991 MB 300D 2.5 Turbo (207000km) (now gone)
1993 Audi 100 CS Quattro (300000km)
1999 VW Jetta TDI (290000km)
2002 Audi A6 3.0 Quattro (150000km)
2005 MB E320 CDI (34000km)