KV DOES NOT EQUAL TO POWER
it is all about Voltage you want to use and finding right gearing.
2200kv motor on 4S = 32560rpm
1760kv motor on 5S = 32560rpm
with same gearing cars will be equally fast.
lower KV motors tend to run cooler as they will draw less AMPS but they need higher voltage. higher voltage = heavier battery however since you dont need to draw as many amps you can have lower capacity battery that will be lighter.
The only rule you would need is in case of longer mains with batterychange where you should limit Wh sou cars with different voltage will have similar runtime (4S 5000mah, 5S 4000mah and 6S 3300mah battery for example)