I would want to put an OM606 in it in the future, but also wouldn't want to pay much for one that wasn't currently running ok. I think the engines in the 1995 ones are much less of an issue at least, but those are even harder to find.

I'm in California so it's probably unlikely for one of those to have a cracked block or head in that way isn't it? The failed ones I have seen usually have the opposite problem where it holds pressure for days after driving.