I am running the Honda genny. Its cost more up front, but well worth it. My stereo which is the same size will kill two batteries in under an hour. The genny set up cost about $1400 with the power supply but in the long run it will save you money. Batteries need to be replaced often when beat up like that. If you really want batteries I would run the Optimas with 4 of them dedicated to the stereo. You can adjust that number depending on your listening habits.
Good Luck,
Wet