I have a 2006 340 Sundancer, not the same boat you have, but I had a real time finding all the sound system parts. Did you check under the V berth, forward, and under the couch (don't forget the aft berth)? The system is actually composed of two amplifiers, and two sub-woofers, one in the cockpit and one down below. Also, the boat came with a small TV over the sink, behind the TV was a hideous maze of speaker wire and odd mini-connectors that broke out the system into cockpit and internal sound systems. It further broke out the internal system into a fore and aft. Our boat is admittedly a "one off", as it is the Fisherman's version with twin Diesel engines. Very few made, and based on the differences between the documentation and the boat, not much on it is standard.
