Are aftermarket upper control arms required on the 2003 - 2019 4Runner systems?
No, aftermarket up control arms are not required on 03-19 Toyota 4Runner. The 4Runner UCA’s provide enough alignment adjustment to set the vehicle within the factory alignment spec range. Lifting the vehicle over 2.5” on some vehicles the stock upper control arms have difficulty getting caster correctly within the factory recommended range. Vehicle set with less than 2.5” of lift can be aligned using the factory upper control arm. For more information contact ICON tech-support (951) 689-ICON.