The stock ignition coils of your 2005 to 2009 Mustang GT were designed by Ford to work reliably, but that's about all they do. Grabbing a set of uprated, performance ignition coils can vastly improve your engine's efficiency and get you more horsepower, more torque, and improved fuel mileage all in one simple kit. All of these Mustang ignition coil options from Stage 3 produce much higher voltages than your stock coils which allows for your spark plugs to produce a more intense spark. The increased spark burns your air/fuel mixture more completely and gets you better performance. All of these ignition coil packs are extremely easy to install and are one of the most hassle-free ways to get improved performance out of our Pony. Once you select a set of coils, make sure to take a look at our 3V Mustang cold air intakes, throttle bodies, performance packages, or exhaust kits to get even better bolt-on performance.