CHANGING THE SPARK PLUGS TO A DIFFERENT METAL CAN HAVE CONSEQUENCES. USING THE RECOMMENDED SPARK PLUGS IS YOUR BEST BET. DON'T BELIEVE ALL THE HYPE ABOUT POWER GAINS... LOOKING AT THINGS REALISTICALLY, YOU NEED TO MAKE ADJUSTMENTS IN FUEL, TIMING, AND INTERNAL COMPONENTS TO REALLY NEED A HOTTER/COLDER PLUG... IF YOUR CAR ISN'T HEAVILY MODIFIED, DON'T SWITCH YOUR PLUGS.