The Bilstein B6 4600 rear shock is a direct-fit upgrade for 2003–2010 4Runner/FJ and 2010+ GX460 applications at stock ride height. The market description notes a 46mm monotube design, velocity-sensitive digressive piston and application-specific tuning to improve ride quality, handling and comfort while using OEM springs and mounting hardware. These shocks are tuned for the listed light truck and SUV applications without requiring new springs.
Bilstein 03-10 4Runner/FJ and 10+ GX460 B6 Series Rear Shock