I think this is a really difficult one. If it were just 71k on the clock I'd say it's worth €5k all day long as it looks super clean, and I'm sure it is as clean as it looks having seen your (first e63) and your e36.
The problem is the mileage will go against the value here but the condition will offset it to some degree. On balance would you get €3,000 for it? I'd say it's worth a shot by advertising it at €3,500.

(But you know you should keep it!)