It's nice but there's no way I would consider paying that much for it...there's really little reason to pay a premium for low mileage in a diesel car. The kinds of problems that plague the W210 chassis are not mileage dependant but are time and climate dependant. Electronics, and HVAC are issues that you will face if that car has 50K or 150K, it's just that with 150K you'll have $10K more in your pocket to fund the repairs.
http://cgi.ebay.com/ebaymotors/1999-MERCEDES-E320-LOW-60k-MILES-WARRANTY-FL-30-MPG_W0QQitemZ300020856213QQihZ020QQcategoryZ6335QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Here you can buy a gasser of the same year with only 60K miles for $10K less...you'd never make that up on fuel savings and you'll still get another 100K miles out of it too. You could probably find a nice E320 for $10K with low miles too if you looked hard. So, basically they are asking nearly a 100% premium for a diesel...it's crazy.