When i set up my system in my car i want to make it so if i fold down my back seat you can see the subs. but there are metal bars behind the back seat in my car. would it harm anything if i remove them? other than the seat saggin back? but if the seats sag back that doesnt matter cuz i dont sit back there and i hardly ever have people in the back seat. also how many subs do yu think is a good number to have in a cav? and what size do you think works best?