I'm new here...I just recently picked up a 2003 540i M Sport Titanium Silver with Black interior as a 'fun project' car and one of the thrust arm bushings was bad (driver's side). A little searching brought up this thread and it was very helpful. I ordered two brand new Lemforder thrust arms from Amazon for $240 shipped to my door. I had the luxury of being able to borrow my buddy's lift to do the work and went to it. I also used my air tools to make things quicker and a LOT easier. I followed the DIY instructions closely but did a few things differently. First of all, I did as nsogiba did and left the pinch bolt on the shock alone. There was no need go through that to get the ball joint off. I decided to use a fork type ball joint separator attached to my air hammer instead of the Harbor Freight tool and it took it out in no time...then just finished unscrewing the top nut and it fell right out. It's so much easier doing it this way BUT if you plan on reusing the ball joint then use the screw type puller instead. It won't destroy the ball joint. The last thing I did differently is use a jack to lift the wheel spindle just high enough to lift the car off the jack stand on that side to bring it to ride height then torqued down the bushing bolt as Quick99Si stated above in one of his posts. The whole job took me just over an hour to do and was a lot easier than I thought it would be. Yes, working under a lift has it's advantages and shortened the time it took to complete the job. Air tools obviously helped as well. The car drove pretty damn well before...now it's just like a new 540! Although, while checking things out before wrapping it up I found one of the sway bar end links had some play so it looks like I have another small front end job soon. I just have to wait for the OEM BMW part to show up.
Thanks to the OP for the great DIY.