[onewhippedpuppy]

I would say $25-30k based on the low mileage. The E39 M5 seems to be holding it's value better than the E60, which you can now buy for similar money.

Great info on this thread, the only common thing I didn't see was the MAF. There's two of them, I believe they are about $400, and they fail frequently giving all sorts of strange CEL messages.

Also be on the lookout for a knocking engine, they do like to spin connecting rod bearings.

The interior is pretty cheaply made, if not taken care of it will show its age with rattles, leather wear, drooping headliner, cracked plastic panels, etc.