Ok bud here we go the volts have nothing to do with it... the lower kv is more tourqe the higher kv is more rpm = speed and also heat when installed into a big heavy rc truck. Therefore you want a lower kv in bigger heavier RC 4x4 trucks. And higher kv in little baby buggies and short course...
Yeah the math basically will work out to be close or the same. But when you take a 4x4 1/8 - 1/5 heavier RC trucks.. You want lower KV. To help combat the heating of you esc and motor. With a higher KV that motor would be burnt out in one or less.. there's alot more involved then how you are...