Conclusion: I have two in a small enclosure behind my rear seats and they kick very hard with the limited power I feed them. I wish I could give them a larger enclosure but space there is not much space behind my truck's rear seats. Very happy with product.
Summary: I didn't buy them off amazon but I have 2 in a sealed box with a Gravity GR1100 amp bridged and running at 2ohms(with the bass boost), you can FEEL the bass!! in the seats, shakes my rear view mirror side mirrors, these speakers are great slap hard wont bring to much attention to your car but sound really good inside, had to dynamat parts of my trunk
Summary: I installed this in my Mercury Sable with a Rockford Fosgate P300-1, and I am definitely happy with the results. My goal was to add a little more low-end to my car sound system, and this subwoofer definitely pulled it off. Not only does it add the lower frequencies, it adds them with definition. Bass instruments sound crisp and clear, and there is plenty of headroom to really crank it. As far as value goes though, I feel like I could have done a little bit better.
Summary: I drive a Dodge Ram Quadcab. I bought ONE of these subwoofers and installed it into a fiberglass enclosure, which I fabricated myself, to fit under the driver's side rear seat. I also installed JL Audio speakers in the stock locations (with no modifications) and the JL Audio 600/6 amplifier. The fiberglass enclosure was built according to the volume requirements, in the subwoofer's manual and it is powered using channels 5&6 (in bridged mode) of the amplifer.