XR Series Ignition Coils provide 15% more spark energy over stock coils, as well as firing performance approaching 40,000 peak volts due to their use of premium, ultra-pure copper alloy windings. Proven to perform in some of the harshest street and race engine environments, the XR Series coils ensure increased performance and maximum power. These coils are direct replacements for factory 2006-current coils and fit/connect like factory for an easy installation. Legal in all 50 states, these coils do not affect emissions and can be installed without any additional modifications.