RE: Which of these motors is best? (different Kv rating)
The difference is in how fast each motor turns on a given voltage. That's what the Kv rating indicates, RPMs per Volt.
The motor with the higher Kv rating spins a smaller prop faster, so it would be more appropriate on a general sport plane. The motor with the lower Kv rating spins a larger prop slower, so it's more appropriate on a 3D plane.
Whether the motor is appropriate or not depends on what a "CAP 32" is, what its power requirements are, and how you plan to get that power.