What is the best setup 8xl and warrior 9920

[maxxdude1234]

I think we are both thinking on two different wavelengths. What I said is correct on a scientific scale, but what you have said is more on the practical scale - and hence more appropriate for rc's. There is no denying that, providing everything else remains constant (gearing, amount of throttle applied, temperature) a motor will draw more current at a higher voltage than at a lower voltage.
The beauty of running at higher voltages is you can gear down, and therefore reduce the amount of current the motor will need to draw - which is effectively what you said, and I fully agree with.

Good talking with you Serum, and I hope we have reached an agreement.