Brushless motors provide a great amount of power to RC racers and if paired with appropriate gearing and high-discharge Li-Po (Lithium Polymer) batteries. Brushless motors are approximately 30% faster than the same size brushed motors, e.g. Brushless 540 type motor 1/10 scale rc cars can give a top speed around 50-60kph while brushed 540 type motors only run about 30-40kph.
Brushless motor needs to work with brushless electronic speed controller and best power source is Li-Po battery which requires a lipo battery charger. Due to the differences on the electronics and power system, it is generally costy to upgrade the current brushed system to brushless, in most cases, gears and shafts need to be upgraded as well to cope with the higher speed.