AST F9X X5M X6M / G0X X5 X6 Adjustable Lowering Spring KitAST Height Adjustable Springs (HAS) Systems are a great alternative to conventional lowering springs. You no longer have to be satisfied with a fixed lowering height. AST HAS systems allow you to adjust the vehicle ride height with the integrated height adjuster even after the kit has been installed. All driver assistance systems and comfort features of a factory adaptive or electronic suspension remain operational and work harmoniously with our