If you want a sub that will fit anywhere check out the little Sunfire sub. It's a 9" square 1500 watts and will blow away subs 5 times its size. It's reportedly ruler-flat to 22Hz and I'd have to agree. It's an incredible sub that will blow your mind when you hear it. It's about $1000 but I couldn't afford it so I bought my Velodyne, bummer. Go check this thing out!