Castle Creations motor and ESC combo recommendations for the Team Associated Pro4 SC10.

Sidewinder w/1410-3800kv - 14 pinion / 54 spur on 2s = ~35MPH
Copperhead 10 w/1412-3200kv - Stock gearing (25/54) on 3s = ~45MPH
Mamba X w/1415-2400kv - 18 pinion / 54 spur on 4s = ~55MPH

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.