I've been following this thread and looking at the Specialty Products bushings as an alternative to new camber arms. I am a little confused. The Specialty Products installation video and some comments from other threads on this subject say you need 2 bushings per wheel and the video shows installation on 2 arms on each wheel. Is that cause the video is really for Mercedes and the XF has only one arm per wheel? MikeR and Max seem to do it all with one new arm.