Grayson does it so they are not responsible if it goes. In there vid they state it is not rated for 4s and may blow the vtx. Many people fly 4s without changing anything. It is up to you if you want to take the risk or change the wiring. Quantum is right about the props. The ones included break super easy. My buddy got his Wizard and went through all of the props it came with in a weekend. He then got some Dal Cyclones, has not broke one yet. My buddy also flew 4s on his stock Wizard. He did not have a problem. I am not advocating either way, just letting you know.