255,xxx showing on my '89 535(M30) by the two previous owners with the odo having quit four years before my purchase, Estimated to be 300k now and after a year off is being pressed back into service for more.
This one had good care, with the head off for a new gasket the hone marks were still clear. I'd like to think the M30 could go another 250k but that is asking a lot. The salty midwest makes the eighteen years required to do so a moot point.