These kits provide the highest quality ride characteristics for your Mustang-II front end. The springs are designed specifically for use with QA1 coil-over shocks and the factory spring pocket. This enables the use of a longer spring, which allows for a lighter overall spring rate. The shocks are designed for high performance comfort, with increased travel for better ride characteristics. Adjustable shock kit has a 12-position rebound valve adjuster for fine tuning ride quality while the economy version has a non-adjustable, ride sensitive shock and is designed for cars lowered 2 inches or less.