Castle Creations motor and ESC combo recommendations for the Kyosho Fazer MK2:

Sidewinder w/1406-4600kv - stock gearing (32/68) on 2s = ~35MPH
Copperhead 10 w/1410-3800kv - 28 pinion / 68 spur on 3s = ~40MPH
Mamba X w/1410-3800kv - 34 pinion / 68 spur on 3s = ~50MPH

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.