KV choices.

[BrianG]

I don't see why the 1800 wouldn't be just fine as long as it physically fits. The larger motor will stay cooler over a broader range of gearing. And if going to Medusa, I would go with an 80mm version for the extra cooling and torque in a truggy. I would only go with the 70mm if you were racing only and for short durations. In that case, less weight and lower torque might be better.