Southpole Man,
Like any other purchase, I encourage you to do your research before you buy. Base your decision on facts, not opinions. Please read the warranties of the different companies and also check to see if the battery you choose is made with recycled lead, it all makes a huge difference. Size your battery based on your equipment and expected drain.
Optima recommends you use a dual-purpose deep-cycle battery for your application which would be our YellowTops. Our RedTops are starter, OEM type replacement batteries and just not suited for aftermarket stereo applications.
Other things to remember, if you plan a custom installation where the battery is going to be inside the interior, be sure to properly vent it to avoid any toxic or flammable gasses, should your battery get overcharged down the road. We offer some YellowTops with vent tubes or you can place the battery in a vented box. Just be sure to use the vent tube, regardless of which way you go.
Thanks, and feel free to ask other questions about our products if you have them,
Bill Howell
eCare Manager, OPTIMA Batteries, Inc.