If you are looking for the best performance for your Mustang Cobra/GT500 4.6L or 5.4L 4-valve engine, you need a set of High Performance Coil Packs! These coil packs will help increase spark energy and voltage output to get more power to the ground! They feature heavy duty 500° Silicone Boots to contain the 24,000 volt spark! Ignition coil packs are often an over looked performance part that can really make a difference under the hood of your Mustang. Great Performance at a Great Price!