These parts are installed onto a Supra's stock twin turbo OEM wastegate actuator to increase it's base spring pressure. This allows the turbos to make more boost. Installation can be done with the turbos and actuator installed on the car, and is fairly simple. Base boost pressure is adjusted by either tightening (raising boost) or loosening (lowering boost) the included wing nut. This is recommended for use with our STU GT28 twin turbo upgrade.