Racer X Fabrication WRX/STI Rear Upper Control Arms

Racer X Fabrication WRX/STI Rear Upper Control Arms

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  • Constructed of 4130 chromoly steel
  • Total weight reduction of 8 lbs
  • CNC machined stud to OEM specification
  • TIG Welded
  • Adjustable for camber correction
  • Designed for racing
  • Black zinc plating for corrosion resistance
  • Made in the USA, at Racer X Fabrication

Install Time: 1.5 to 2 hours
Alignment recommended after installation.
Installation Guide

The Racer X Fabrication rear upper control arms for the 2008+ Subaru WRX / STI are the best option for adjusting camber on the rear of your vehicle. The pivot point allows for minimal impact on toe during camber adjustment. The tubular design allows for a weight savings of 4 lbs per control arm (8 lbs of total weight reduction), by far one of the largest weight savings for suspension components. The upper control arms retain the OEM wire harness mounting bracket and use urethane bushings with zinc plated steel inserts to reduce movement and increase response.


The rear upper control arms are constructed from 4130 chromoly steel and TIG welded on jig fixtures that were designed from the OEM data points. The rod end stud that connects the control arm to the rear hub assembly is CNC machined to exact tolerances using the OEM CAD model to ensure a perfect fit. Finally, the control arms are zinc plated with a black finish to protect against the elements and prevent corrosion.


  • 2008+ Subaru WRX / STI


Rear upper control arm is pre-assembled with the following components:

  • (2) 4130 Chromoly upper control arms
  • (4) Urethane bushings
  • (2) Rod ends
  • (2) 2 CNC machined studs
  • (2) 1/2" bolts for studs