The speakers didn't add bass... they actually took some away. I have the standard system, and I'm currently in the process of building a fiberglass/wood sub box for the factory location (behind the panel in the cargo area). I'm almost done and I'll post pics soon, but basically once the panel is back in place, it'll look exactly like the factory woofer box with a nicer speaker in it. It just takes advantage of the airspace a little better and is constructed of better materials so it's more rigid. That should take care of the bass.