There are only a few bushing on the car that require this. The Bentley only says it about this bushing (in red):
The instructions for the SPC aftermarket control arms say also to do it for the center bushing in the LCA for the same reasons (in blue, same arm). That makes sense although there is probably a lot less rotational movement there.
Then if we are going to do it there, might as well do it on the rear toe arm as well of that is ever getting replaced, for the same reasons, and that one probably does have a lot of rotational movement, same as the LCA. But the Bentley doesn't say that one either. That one is also in blue, and applies to the rear only.
For that one in red, it really does hold the arm in place pretty well, when you are doing work like removing the axle or changing the strut, you have to release that bolt otherwise the arm doesn't pivot down nearly enough. I wonder how much that contributes to the spring rate/damping? I have monoballs in the front so I don't have to loosen it when doing work, but in the back I still have the rubber bushings and so I do. That is one area where I really like the monoballs, when doing suspension work, even if it is infrequent
