it wouldn't hurt though. I did for 1200 watts rms between my 2 amps
you dont need a second batt for just 1200w.
i run about 2000w RMS with just one battery. my personal fav are the optima batteries, ive been using a yellow top for years with no complaints.
the red optima have higher cca, but the yellow have more then enough to start the car and have the better deep cycle performance.