UMI  Performance extended length control arms are designed to properly center the  rear wheels in the vehicles wheel well on the Impala SS. These control arms are  extended 5/8” but also feature additional adjustment to perfectly center the  rear end. The adjustment allows the user to lengthen or shorten the control  arms an additional ¼” beyond the already extended 5/8 of an inch. The control  arms are built from 1.500” DOM tubing and fully TIG welded for the utmost in  strength. Control arms also feature the correct provisions for adding a stock  or aftermarket sway bar. The provided sway bar holes are reinforced with a  0.120” all thickness steel sleeve TIG welded and sanded in place. The sway bar  attaches to the control arms using a billet aluminum spacer contoured correctly  to follow shape of the round tubing and properly attach the sway bar to the  control arms in the factory location. NOTE: In some cases,  depending on ride height variation, it may be necessary to install a longer  driveshaft when using extended length control arms.