Endlinks on your Subaru transmit the energy of the sway bar to the suspension control arms. OEM endlinks are only adequate on a totally stock car, once the suspension or tires have been upgraded they become a weak link and must be replaced.
PERRIN polyurethane rear endlinks for your 2008-2013 WRX & STI and 2013 FR-S & BRZ 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.