Everyone I know with W140's around here gets screwed with taxes. They go by blue book value until the car is 10 years old. So they said my friends dad's S600 was worth $40k, and my friends S320 was worth almost $20k!

The fight it and win, but its a PITA.
I said to him if the insurance company is willing to give you $20k you should drive it into a wall and take the money!