Did this job yesterday afternoon, so I thought I'd put some notes here.
I borrowed a ball joint press but found I didn't actually need to disconnect the ball joints -- once the long bolt was out I was able to push the idler arm sufficiently out of the way. Naturally I had both front wheels off the ground, so they were able to assume different angles to allow for the different geometry.
The hardest part was getting the old bushings out. One of the manuals shows a guy pulling them out with his fingers, which I think is supposed to be dry German humor. I tried using the old bolt as a punch, but didn't get anywhere -- I think maybe the rubber had just enough give to absorb the hammer blows. What did work was steady pressure. On the bottom bushing I clamped a pair of vise grips on the outer sleeve, then heated the bore with a torch until the rubber softened up; after that I was able to twist it out. The upper presented an access problem that ruled out that approach; I ended up setting up a makeshift press with a 13/16" spark plug socket, a socket extension, and a bottle jack. Once I had some pressure on the upper bushing, I did the heating trick again and it slid right out with a few strokes of the jack. It's hot enough to come out right around the time the accumulated oil drippings catch fire.
The rest was easy. The MB service manual mentions using oil on these bushings, so I put a few drops at the joint between the inner and outer sleeve on the new ones, then rotated the inner sleeve to work the oil in. I used Sil-Glyde on the rubber to make them easier to press in, and used the old bolt and nut to press them into place.