Yeah the ground controls are really nice for auto-x. They use linear springs, not progressive. So you never have a point where the spring transitions between the softer progressive rate to the harder normal rate, they are always the same spring rate and more predictable and more responsive. Also ground-control will let you pick your spring rates over what they would normally be, for a small fee. And Koni yellows would be a pretty hard strut to beat with ground-controls. Plus I'll add that they have a excellent technical department.