Castle Creations motor and ESC combo recommendations for the Vanquish VS4-10:

For Lighter Rigs (under 6lbs) and strictly low speed crawling:
Mamba Micro X2 w/1406-1900kv on 3s or 4s - Good all around crawler setup. Will need an external BEC or direct to battery servo.
Mamba Micro X2 w/1406-2280kv on 2s or 3s - Great for comp rigs. Will need an external BEC or direct to battery servo.

For Heavier Rigs (under 9lbs), more aggressive crawling, and light duty trail running:
Copperhead 10 w/1406-2280kv on 2s or 3s - Good BEC for single servo. Will need external BECif running rear steer or winch.
Mamba X w/1406-2850kv on 2s or 3s - A slight step up in wheel speed if you're a bit more aggressive driver.
Cobra 10 w/1406-2280kv on 2s or 3s - The gold standard of crawler setups. Hill Hold feature allows for guarantees the motor will hold at any angle.

The 1406-2850kv paired with with the Cobra 10 is also a good choice for 2s and 3s if you want a bit more wheel speed.

Always monitor ESC, motor and battery temperatures on new setups or when changing gearing or batteries.