BMW E46 M3 - Turner Motorsport S54 Power Pulley KitGains of up to 10hp on a stock M3! The idea of power pulleys is simple. The less effort the engine puts into running accessories such as the water pump, power steering, pump alternator etc., the more of that power can be used elsewhere your wheels! The way this is done by reducing the rotation of the pulleys by as much as 10 20%! The end result is more horsepower at your disposal. Turner has done extensive testing (on and off the track), to ensure