Mike,
Since you have a Late 280sl, the install may be even a bit simpler. The starter is held on the car with Two bolts, one is accessible through the trans tunnel as described and the other is easily accessible from underneath. The other attachments are all electrical. Since yours is a late 280sl, your electrical connections should be a direct match to the new starter. There is nothing else to line up or synchronize --- if you have it flush mounted like original, that should do it. It really is that basic.
First disconnected the battery, then I removed the upper bolt from the trans tunnel access. With car jacked up on right side, and safely supported, I then removed the lower bolt from underneath while supporting the starter with one hand. Once second bolt was out, I pointed the starter up, so all connections were facing down. While resting the starter on steering arms and such, I was able to disconnect all wires and pull it out. Placed new starter in same position with it pointing up and connections pointing down and fitted all electrical connections (not fully tight). Placed starter in position and first loosely put in the lower bolt, then was able to put in upper bolt by hand from underneath. Lining up was not difficult since I left it all loose. At this point, I tightened all electrical connections, keeping it away from the exhaust manifold. Then I fully tightened both upper and lower bolts. Reconnected the battery and voila.
Good luck, let us know how it goes.