Just got these Saturday from UMI, they are the new Roto Joints that replace the old bushings in the upper rear end housing. They were simple to install with some mild taps of a 2lb hammer and a large socket. A big thanks to Ryan (and Ramey) for letting my Elco be a test vehicle. Can't wait to hit the autocross track this year to see if they are an improvement over a bushing. Looks like it will let the rear travel better with less binding.