Tell us about yourself!
Also it has to match the motor. Brushless ESC for brushless motors and brushed for brushed.
You have probably already solved this but on brushless motors the wires doesnt matter. Just connect the wires any way you want. If the motor spins the wrong way, switch any 2 of the wires between esc and motor.
Higher kv motors have higher top speed but lower torque. High kv are good for light rc cars or small prop aircraft but low kv are good for heavy stuff like bigger props, or moving a human. 2x1000kv with enough volts MIGHT work if you are light and only run on flat ground.