Subwoofer

I own a 2001 Lancer GLI 4dr Sedan. i am wanting to put in a subwoofer, but i don't want to take up a lot of space, i was thinking of placing an Slim profile Pioneer 8 inch and buidling a little spacer so i don't have to cut a hole in the rear dash. What i want to know, has anyone else tried this or what can you recommend for me to do, so that i can still have a sub, but not take up alot of space.

Well I got an idea for u its what i did for my wife's car..........
get the new pioneers slim profile.... these where made for pickups with no room place them in your trunk in a slim box and the best part is that because they where made fot truck they r well made and strong so u dont have to worry about nothing braking the cones if u place them the right way....and u could even go up too 10 even 12 if u want im me for more info