Just to properly close this thread out:
Well, this job was not too bad. And to answer Sixto's question, there is plenty of room to move the bolt out and put the new one back in on the 560.
I used a very long extension on the head of the bolt, going in from the top, and wedged a wrench on the nut to break the old one loose. No sense in laying on the ground to do that. Much easier this way.
I wouldn't do that to tighten the bolt though. All those extensions make the readings just plain wrong! (I used to have a table telling you how to figure it out) Getting all that torque on the bolt laying on your back is some fun though. 180Nm, I think.
1989 560SEL (172k)
1989 325IC (122K)
2004 Suzuki Volusia LE (3500 miles)
2005 Yamaha Road Star (20 K miles)