SuperPro Front and Rear Performance Sway Bar Upgrade Kit | 2015-2019 Subaru WRX (RCWRX050KIT)2015+ Subaru WRX Roll Control Sway Bar Kit by SuperPro The SuperPro Roll Control two position adjustable front sway bar is 26mm solid and the rear is a three position adjustable 24mm solid sway bar. A All this adds up to a vehicle that is a balanced upgrade by assisting tire grip and this becomes an ultimate handling package upgrade. From all our testing, this what we recommend as a good starting point: Stage one is to set both bars to the hardest