I have had 3 123's that 290K, 375K and 475K on them respectively. I know that the older diesels can last that long. I am sure the 124's can last that long. But, I had no idea that the newer ones were as durable. Look at this car - 300K on a 1997. That surprises me.
http://cgi.ebay.com/ebaymotors/1997-MERCEDES-E300-DIESEL-ECONOMICAL-LONG -LASTING_W0QQitemZ170056174121QQihZ007QQcategoryZ6335QQrdZ1QQcmdZViewIte m Donald H. Snook 1990 300SEL 133K