Rc Cars are the best if you want to have some fun there are many types of rc car theres rc cars that work with batteries and gasoline.
Motor are very important to an Rc Car because that's what makes the car move if the rc car doesn't have a motor it wouldn't be able to move.
There are different size motors as you see on the images up big and fast car usually have bigger motor small cars ussally have smaller motor.
The servo is a very imortant part of an Rc Car because that is what makes the car turn to the left or to the right some cars don't have a servo they just have another dc motor but that's on on small cars but on profesional Rc Cars they have a servo.