I just replaced the track arms on my S, the arm uses a ball joint...I cant see how a bushing can do the same job ??
You can take yours off and "peen" the rolled flange to tighten one up....not sure how long this will last...but you could try it and see.
Boxster Control Arm Repair - 986 Boxster Suspension, Brakes, and Wheels - RennTech.org Forums