Perrin Polyurethane Rear Sway Bar Endlinks - Subaru WRX & STi 2008-2014 OEM steel endlinks are small, flimsy and can fail if a larger rear swaybar is installed. OEM endlinks are week and will flex greatly after installing a stiffer aftermarket swaybar. This flexing makes your stiffer aftermarket swaybar feel less responsive. PERRIN polyurethane endlinks are made with stiff polyurethane bushings pressed into 6061T6 aluminum arms to provide a solid connection between your swaybar and chassis. This translates into a more predictable and better handling car.