Specs

This is not true on a '99+ GT. A street set of pulleys will get you a dyno verified 9 hp to the rear wheels without causing any heat or electrical problems. The issues were with the 5.0 and most likely caused by pulleys made for the strip. I had even ran a set of street pulleys on an '89 GT for

7 years without any heat or electrical issues. Granted, I had already installed a high quality 180* thermostat and replaced the Motorcraft battery with a Diehard. The gears will improve the acceleration by allowing the power you have to be used at a lower rpm but the automatic computer will need reprogrammed or chipped for the speedo to be correct. A CAI will only get you a few horses for a similar dollar amount as the pulleys, and the free flow filter that comes with it more than likely attributed to the power gain.