I just bought a 2009 27FB Ocean Breeze and I like my audio to sound good. My Ocean Breeze came with the audio upgrade and I can say I'm less than impressed with it. The Sony CD/DVD player is not very good and does not let you adjust the sound other than the dumbed down features. The speakers are mediocre and the sub woofer is a cheap one.
My first thing I did is replace the sub woofer with a 6W0 JL Audio sub woofer. I just happened to have a 6 inch JL Audio sub woofer laying around the garage from Jeep Wrangler I had put it in several years ago. The Jeep is long gone but I still have the sub woofer.
It took five minutes or 1/4 a beer for those who measure installations with beer. All I did was take out the old sub woofer, disconnect the wires, reconnect the wires to the JL sub, and screw it back into the box. I then adjusted the bass to accent the music I listen to.
Future upgrades include the speakers, head unit, and better amplifier for my sub woofer. More to follow in the near future. Below are some pictures of the old sub and new one. You can see the difference in how they are built.