Unless you are lucky, you will get about what you pay for; probably a little less. The pre-purchase inspection and service histories are all important. At that mileage most or all of the suspension will likely have been changed or need changing. The cat and exhaust system should be inspected. A valve cover should be lifted to see if there is sludge build up. The timing chain and rails should have been swapped out. The tyranny should be inspected. A close inspection for rust and accidents should also be made. Hopefully the car will have been mostly used for hiway trips. If you find a 400e that is fully restored and in really good condition, you can expect to pay a lot more than KBB or NADA values. Otherwise KBB and NADA guidelines will be.....good guidelines.
All that said, the 400e is a very nice example of MB craftsmanship. It is a pleasure to drive and made for about 20 years of service life, or so I hope!
