can you put a supercharger in a subaru impreza and how much would it be and which one is easier info on the above two topics plz

you definitely want a turbocharger over a supercharger. superchargers sap your engine power to crank the supercharger to increase airflow into the engine, your get more responsive boost but a turbo is better, more power. and if you have and impreza you might be able to find a turbo off an sti at a junk yard or something or you might be able to get one from a subaru dealer.

its going to cost a lot of cash

Well to answer ur question, superchargers r going to be the most reliable way to Forced Induction, although l prefer Turbo's. also if ur going with F l (Forced Induction) ur going to need to upgrade engine internals, so the high power u will be puting out wont blow ur engine. impreza is arent generally made for F l which is why Subaru came out with the WRX & STi Models which come stock turbocharged.

if u do go the turbo route - turbo-kits.com
i would say just under $4000 including installation costs

but that site will give u a good price & going to ur local shop will tell u labor costs