I also live in So. Cal., and habitually look at the prices of used Mercedes everyday, and $10,000 for a '92 400E is a good price, especially with the service record at Fletcher Jones.
I'd have the timing chain checked for stretch right away. You're just about due for a timing chain replacement, along with new guide rails and probably a new tensioner.
The car must be in great shape.
How is it optioned? What color is the interior / exterior?
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".