Just to add my two penneth.........70k would not freak me out nowadays...yes its a higher average than normal, but with build quality nowadays 70k is probably like 25k on a car 15 years ago.
I read a report recently by the guy who heads up Glasses Guide, the Trade Bible, and he mentioned that any modern car nowadays is capable of hitting 300,000 miles before its fit for the knackers yard.
He says that as long as a car has been serviced to the specified intervals then engine wise you should not have a problem....naturally you will have to replace shocks, suspension parts etc etc along the way, but thats to be expected. Modern oils, computer aided design and testing are seen as the main contributors to this turn of events.
He goes on to say that the only reason older cars are worth nothing is down to image and buyers always wanting to have the latest model of whatever it may be.
This article then went on to say how there is now a marked increase in the number of people giving up more expensive cars and jumping into 10 year+ old cars and just running them until they drop as you avoid depreciation and many 10 year old cars have all the items you want such as Air con, ABS etc etc, but without some of the sophisticated electrical systems that make new cars nowadays such a problem to fix when they go wrong......the current E Class being a case in point.