An aftermarket adjustable track bars is not required but is needed to center the axle underneath the vehicle correctly. ICON always recommend using an aftermarket track bar on solid axle applications to adjust for shift in the axle position due to lift. There are several Stage Systems that have a track bar already included but for systems that do not, the 03-19 4Runner will utilize the following tack bar:

54200 - 07-UP FJ/03-UP 4RUNNER REAR ADJ TRACK BAR KIT

For more information contact ICON tech-support (951) 689-ICON.