I replaced an older A-Trend sealed box with this ported Fox Acoustics box and it made a huge difference with my JL 10W3 (4 ohm) driven by a JL XD600 (400w RMS into 4 ohms) in my 4th Gen Ram. It hits several Hz deeper, higher decibel SPL, yet still gives the same punchy impact with mid bass kick. The fit is a little tight with the included lifting brackets...you may want to go with a slightly higher spacer with longer bolts, especially if you go with a high excursion sub. Overall though, the build quality is excellent, true 3/4" very dense MDF with a double baffle with an expertly applied bed liner finish. I highly recommend this sub box!