kV is the motor’s rpm per volt with no load. Lower kV gives more torque, higher kV gives more top speed for the same battery.

Brushless is more powerful, efficient and longer-lasting, and is the standard for performance. Brushed is cheaper and simpler for beginners.

Match it to your car class and the ESC. Bigger motors and lower kV suit larger, heavier cars, smaller high-kV motors suit lighter ones.