I'm going against the grain in this thread. Bazooka subs are excellent quality and sound IF you know what you are doing.
First of all, DO NOT buy the self amplified bazookas. Their amplifiers suck. Buy the RS series non-amplified bazooka tube, 10" preferrably along with a good quality 250 to 500 Watt RMS single channel subwoofer amplifier. You also want to get a separate crossover if it is not built into the amplifier to prevent the highs and mids from going the the woofer.
The next step is location. It is very important to face the bazooka woofer toward a small corner so the bass can reverberate properly for a deep rich sound.
I had to go with tube enclosures with my boat due to the limited opening space to a large unused space. If I went with a traditional subwoofer enclosure, I would have had to build it inside my boat. I originally was going to do that. But it is not an ideal thing to do if you have limited time.
Instead, I chose to place my 10" Kenwood in parallel with an 8" bazooka, down to 2 ohms at about 300 watts, behind the false wall in front of my driver seat. It sounds excellent and has pounding bass with no distortion.
Here is a pic of the location:
http://www.wakeboardindiana.com/portal/DesktopModules/EditPictureGallery.aspx?username=mygreenmonster.co m&GalleryName=Boat%20Audio&galleryid=8&picid=51&Pa geIndex=0&PicPageIndex=1#Pictures