All passenger vehicles have shocks. Usually, there are two shocks on the front and two shocks on the rear of the vehicle. Shock absorbers provide a basic function which is to prevent the vehicle from bouncing and to control the speed of weight transfer especially on performance vehicles.
Shocks come in a variety of compression and rebound settings. You can tune your shocks to handle and give a softer or stiffer ride by utilizing different shock absorbers with a variety of compression and rebound settings.
Shock absorbers are very important to the handling and performance of race cars. Shocks greatly affect how a race car enters and exits turns and the time it takes to transfer weight from front to rear and side to side which is very complicated.
Most shock absorbers are not difficult to change provided you have the necessary tools. Many times the nuts and bolts are rusted and very tight or may break and need to be replaced.
The basic components of struts are the shock absorber and the spring which are combined to make up the strut.
The spring holds the body of the car off of the chassis and absorbs energy when the vehicle hits bumps and dips in the road. Without the shock the vehicle would bounce up and down excessively.
Struts are a structural component of the suspension and take the place of the upper control arm. This design limits the adjustability of the camber and caster.
The top of the strut is usually mounted to chassis and on the bottom of the strut is usually mounted to the lower suspension knuckle of the vehicle.
Replacing the strut requires specialized tools and I do not recommend attempting to remove the spring from the strut unless you have the proper tools and training. The spring is under pressure and could cause bodily injury if released improperly.