For non-California vehicles only. Premium fuel required for maximum performance. Reverting to stock calibration with non-production tires/gears will result in error codes. Loss of functionality of critical systems may occur. Calibration and ProCal 4 tool are VIN locked to a single vehicle and are not transferrable. Please contact the Tech Line with additional questions. ProCal 4 software only available for Windows 7 or greater. Will NOT work with Windows 10. ProCal 4 tool receives periodic firmware updates for greater usability and additional features. Please connect tool to PC periodically to receive the updates automatically.