I've always had two 12" subs in my Jeep up until now. I have a kid and now need the cargo room more than I need the extra bass. So, I set out to find the ultimate compromise between efficient use of space, and thunderous bass. I looked at the JL Audio Stealthbox, but the price was seriously prohibitive, and I thought that for the price I could do better than a 12W3 sub for that kind of money. Most recently I had 2x12" MB Quart subs in an enclosure that I made myself, which took up most of the rear area of my KJ. What I settled on is a custom enclosure by subthump.com, and a single 12" subwoofer by Dayton Audio. The sub was about $160 plus shipping, and the enclosure $120 plus shipping. The enclosure is only advertised to fit a 10" sub, but mine is being made for a 12". The air space is going to be kind of on the small side for the driver, but with some poly fill it will work really nice. The sub is seriously high quality...600w RMS, GIANT vented magnet, aluminum cone, and will work well in a small sealed enclosure. The pics of the sub are mine, the pics of the enclosure are from the website since it hasn't arrived yet. The sub will be powered by a 1000w Phoenix Gold amp I have mounted under the rear seat. The rest of my system consists of an Alpine head unit and Pioneer door speakers.