just buy the bushings and ball joints and nuts and bolts from bmw dealer , the cost is similar , maybe cheaper due to postage costs.
here is a link to replacing , about halfway down the page , upgraded bushes but procedure is similar.
http://www.xoutpost.com/bmw-sav-foru...tempt-2-a.html
the bmw bush is 66millimetre so you will need a socket or tube with 67mm or more inside clearance and one with maximum outer diameter of 65 mm .
bmw recommend replacing bushings once only so if you have high miles they could have been replaced previously but I think most folk would have replaced the arm with bush fitted ..