AST Suspension Lowering Springs (35mm/35mm) - 1986-1996 Audi 90 Quattro Coupe 6CYL (89)AST Lowering Springs for the 1986 1996 Audi 90 (89) are manufactured from a premium high tensile chromium silicone wire which is handpicked by AST engineers for its quality and metal consistency. Each spring is cold wound and then heat treated to increase hardness and reduce internal stresses present after winding. Each spring is then individually shot peened, phosphate treated and then powder coated to outlast even the life of the vehicle. Features