SUPERCHARGER UNIT
First thing is that both of these units are used to increase the boosting power of engines and both works as air compressors. They compress the air and increase the amount of oxygen atoms in a unit air volume so the engine will get more oxygen at a unit time. This leads to more power output ( Increases the horse power). So a car with turbo or super charger will have more horses under their hood than a same type of car that does not have any charger.
TURBOCHARGER UNIT
Most people have a wrong idea that supercharger will give more power always than a turbocharger. That mistake has happened since the word 'super'. Turbo works with the power of useless exhaust gas of a engine but supercharger will absorb some power directly from the engines main output mechanical power and this decreases the amount of power we are using to drive our car! But supercharger has good throttle response because it drives directly by engine. But in order to get the maximum effect of the turbocharger, engine must work at high RPM such that more exhaust gas runs through the turbo. This means we have to always drive at high RPM to get the maximum power.
INTER-COOLER UNIT
Turbochargers are commonly used than superchargers because of energy efficiency described above. So my suggestion to you is to use a turbo if you want to increase the boost of your car engine. Also use an inter-cooler device between engine end the turbocharger to get the maximum out of a turbo unit. Good luck for Power!