ORIGINAL: clamber
So confusing
My bad. Pretty much, higher kv just means that for every volt the battery gives the motor, the motor will try to make 'X' amount of power. So a lower Kv motor is doing less work, and a higher kv is doing more work for the power it gets. If you geared up a low kv motor, that's getting more speed and running hotter, just like a higher kv. With the same gearing, the higher kv spins more Rpm, but it will always heat up more. Different cars have different systems. The on road cars are good with 6900/7700kv mambas. The offroad is best with 4600 or 5700, although I've heard the 5700 runs pretty hot.
It all depends on what you want. Just look at what people gear the MM, then look at what they gear the vxl's. They both have similar performance because you can change the gearing.