Let's see....in my truck I have two diamond 10's behind the seats, and the newest Alpine head unit, I have 500w mono amp to them, and it's not that loud. I dont want performace out of my truck. so I put a system in it.

However, in the Civic I have an older Alpine head unit, Diamond Audio 6.5's in the doors, and Diamond 6x9's in the rear, and 2 sets of tweets, factory one's in the doors, and a set in the A/C vents. No subs, just loud enough to hear. I would rather spend money on performance.