We have finally finished our S197 Mustang Street/Race Extreme Joint lower control arms after several years of development and testing. These are the same as our street arms except we are using what we call an extreme joint in place of our poly-ball bushing design. This extreme joint design has a steel metal ball that is captured in hard polyurethane cups which makes it act just like a spherical bearing to completely eliminate any bushing bind commonly found in these lower control arms. Just like most of our other suspension parts these have a lifetime warranty on them. If you have any questions you can contact us or any of our dealers for details.