Thanks for the reply, and the link. I had found the Popular Mechanics page before I came here. The battery is new. I changed it out because I thought the previous battery was the problem, and it was time to get a new one anyway. It clearly wasn't the problem. I was just hoping someone might know of something specific to the Titan, or the pioneer 820 stereo.Here's a great step-by-step on figuring this out. I suspect it's either one of the new adds or the amp/stereo. But it could just be a short. There is also the off chance it could be a dead cell in the battery, so you should consider having that tested, as well.
How to Find and Stop Car Battery Drains ? DIY Car Battery Drain
Thanks again for the help!