I originally purchased the behind the seat enclosure with 2 6.5 subwoofers. Coming from a JL setup in my previous truck, I kind of figured this may not satisfy my specific needs even though it sounded better than the 10 inch woofer I started with. So I decided to upgrade to the 4 6.5 woofers for the underseat enclosure based on recommendations from the team, and I'm simply blown away. This box delivers deep bass and I'm only powering it with about 600 watts. This box is way beyond my expectations of delivery deep, accurate bass.