I would look at the 50 mm medusa. They make up to a 4800 KV with the 1/8th inch shaft. I have a 2000KV 60 mm in a Truggy and it runs great. I am considering a 50 mm 4800 KV to run on 2S in my BJ4WE The 4800 is just to many KV for 3S that will turn over 55,000 RPM. That is why your 5700 is hot it will turn over 70,000 RPM. Remember it is Voltage 3S peaks at 12.6 volts multiply this by the KV rating and this will give you the operating RPM I won't try to go much over 40,000 RPM I would want a little more than a 3200 KV for 3S. The Medusa is a heck of a motor for the money. The Neus are larger diameter and might not fit some cars. Neus are 40mm where Castle and Medusa motors are 36mm.