The Z-link is adjustable for rear steer also. It is less adjustable than the four-link, but can be made to steer. Remember, when choosing spring rates in the rear that most swing arm designs where the spring is mounted on the forward link instead of on the axle tube either clamped or on a birdcage, that there is a motion ratio. The car "feels" about half the rate of the spring. The motion ratio is squared and multiplied times the spring rate to find the wheel rate. This is very important to understand.