Castle Creations motor and ESC combo recommendations for the Axial Capra:

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 BEC if running rear steer or winch.
Copperhead 10 w/1406-2850kv on 2s or 3s - A slight step up in wheel speed if you're a bit more aggressive driver.
Mamba X w/1406-2280kv on 2s or 3s - The gold standard of crawler setups. Powerful BEC runs most dual servo steering setups. The Aux wire set for drag brake adjustment is a super handy feature.
The 1406-2850kv paired with with the Mamba X is also a good choice for 2s and 3s if you want a bit more wheel speed.

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.