I have been lucky enough to always have a great stereo in my boat. But after a recommendation from a friend I installed a 12 from http://sundownaudio.com/
. My life was changed. The bass was so strong not only could I feel the bass on the rope behind the boat, but I could hear it too. Keeping the sub in the space under/behind the passenger seat under the head unit in my X-star, at 3/4 power it has enough air displacement to move the cushions around. My girlfriend cant even sit in the seat with the music up, because it shakes her too much. Your eyes vibrate out of your head. The thing is sick. Full, whole, sound. I have gained a new respect for bass players since this thing was installed.
The owner helped me with every step, from the box, to where it would give me the best sound. Its defiantly worth a look.