Here's the Kelley Blue Book site:
http://www.kbb.com
There's a difference between what you're likely to pay an individual vs. a dealer and I don't just mean an MB dealer - any dealer.
According to KBB, this car is worth about 5 grand from a private party.
I got hung up in all of this "blue book" stuff awhile back, then finally learned it means absolutely nothing, especially when you're working with a dealership(MB or indy) that makes a living selling cars.
I'm not suggesting that the $11K car is worth this amt. I'm saying that you might end up spending $6K on the $5K car to get it up the same level the $11K car is at.
Make sure you pay a REAL MB tech to go thru either one of these cars with a fine tooth comb and realize you're looking at a 15 yr. old car. I don't care how well these cars were maintained, they both need something. The question is what?
Good luck.