In car's front suspension, shock absorbers are one element with a spring and shock absorber bearing. If you want to dismount a shock absorber you must first take out a wheel and sway bar end link, after that you can it out. You don't have to unscrew it from the top of engine compartment.
If you want to disassemble it into previously mentioned three parts you must use a machine called spring puller which stands next to a pillar in your workshop. A few seconds later after selecting a part that you want to disassemble you will receive it "in parts". If you want to put it into one part you must repeat the action but, during the process of mounting, you must select which parts you want to use.
Rear suspension is easier because in normal cars shock absorbers and springs are placed independently and you don't even have to take out wheels in order to change them.