Castle Creations motor and ESC combo recommendations for the Rlaarlo Omni Terminator (1/10th):

Copperhead 10 w/1406-2850kv - 19T pinion / 65T spur  on 3s = ~35MPH
Mamba X w/1410-3800kv - 16T pinion / 65T spur on 3s = ~40MPH
Cobra 10 w/1412-3200kv* - 24T pinion/ 65T spur on 3s = ~50MPH

*Note: Some modifications to ESC and/or servo mount may be required to fit 1412-3200kv motor.

Note: All speed estimates are with stock tire diameter, high quality batteries and appropriately sized battery connectors.
Always monitor ESC, motor and battery temperatures on new setups or when changing gearing or batteries.