Cranking or deep cycle for stereo? Many of us have converted to a two-battery setup. Otherwise, cranking batteries are fairly generic, you get what you pay for. The previous owner of my boat put in a very expensive sealed gel battery. I can't say that I would have bought one.
I then converted it to a two battery setup anyway, and use a Deep Cycle for the electronics and stereo. It really keeps the load/drain off my cranking battery. Your biggest issue is if it fits in the tray. Sorry to say, it's not the rocket science that some make it out to be as it is not really run in extreme conditions. (cold)
One good argument could be made on a sealed battery that could stand the bouncing. That may help justify the sealed gel battery.
Good luck,