but I'd pass on the 600. The twelves are just too expensive to operate, and should you have a major problem it can quickly turn into a catastrophe. The W140 is expensive enough to look after without the complications of the twelve. At least these cars are the later 140's, so many of the issues should be adressed (evaporator, wiring harness, door and trunk closers). Think carefully here as even though the 96 up cars are much better, the W140 is still, in my opinion, one of MB's worst mistakes. For that kind of money, I'd much rather have a later W210, which is also not perfect, but probably new enough to be in warranty.
Again, this advice is worth what you paid for it!.....