What Optima or other deep cycle hi-power battery to use?

I did a search and didn't come up with much. My alternator just died on me on the 4th of july :( so I put a new one in and now I'm really watching the voltmeter, with the ac, lights, and stereo on today it was bouncing around 13volts. Soon I will be putting in another amp and a sub (and a 1.5 farad cap as well) and want to make sure I'm not beating the crap out of my new alternator so.......

What optima battery or something similiar easily would fit in my 95 trans am and would help remedy my power situation? Thanks!

the cap is a good choice and will settle things down a bunch. As far as the Optima goes, look for the one with a red top. You don't need the "yellow" (deep cycle) battery unless you plan on running your stereo for extended periods of time with the engine not running. Deep cycle batteries are not designed to start your car very well. They are designed to supply power for longer periods of time and be able to recover well from a complete discharge w/o ruining the battery itself. Optima does make a dual purpose deep cycle/starter battery but it's 'spensive'.