[starscream]

I've run many many setups and I personally have not seen any performance advantage of either as long as we're not talking in extreme's.

I mostly run 1/8th conversions so I try to run setups that keep the rpm similar to the nitro engine used for the vehicle as this tends to keep gearing options more feasible.

I've had success with motor setups ranging between 24k to 40k but if I had to choose I'd go with a lower Kv simply because gearing up with pinions is easier to manage, bigger pinions tend to mesh better than smaller ones, changing pinion gears is a lot easier than changing spur gears, and I run mech rear brakes so motor spacing from the brake calipers is crucial and easier to obtain with larger pinions.