Qs about Specialty Camber Kit

Hey guys I did some research and saw some kits put out by Specialty Products Camber Kits…what is the bushing made of, poly or rubber? Either way, are there any problems with squeaking etc. How is the adjustibility? Has anyone used the one that replaces the ball joint? If so, how do you guys like it? I like the fact that the products are made to look almost like OEM parts, and don’t look like monster giant pieces of metal that still need shaving to properly seat there.
ball joint correction:
http://www.specprod.com/TEMP_DIR/TEMP_67130.HTML
Regular front correction:
http://www.specprod.com/TEMP_DIR/TEMP_84945.HTML
Rear:
http://www.specprod.com/TEMP_DIR/TEMP_67030.HTML