Kit GM Pro Coil Alum S-Adj 15-300 Are you looking for a front and rear coil-over system that is designed specifically for your 4th gen GM F-body vehicle? QA1's 4th Generation F-Body Pro Coil System is completely engineered with you in mind. With your choice of double adjustable, single adjustable or Drag "R" Series valving options and multiple spring rates, QA1 has a solution for you. Choose a spring rate and adjustability that fits your driving style, adjust the valving to match and you are on your way. These shocks also utilize a fully threaded body that allows you to adjust your ride height for the perfect stance or to finely tune the weight balance for superior handling.