thanks everyone for your replies and insight. It's great to be able to exchange info and help each other here, so here's what I ended up doing.
This past Sunday, we went shopping and our last stop was near an O'Reilly's auto store. The car was getting harder to start after each location we visited. Well, it finally happened, the car wouldn't start, but we were parked a couple hundred yards from the store, so I went down there, the employee came and tested the battery, show'd me the results, and it was a gonner.
Ended up buying their premium battery, that has 950 cca, which is better than the OEM, plus, it's made in Germany, specifically for my car, and fit's perfectly. We hooked up a core to the charge terminals under the hood to keep the car with some power, replaced the battery, and now, two days later, it shows no sign that it is different. All settings are still there, and it starts like it used to. We are very happy.
To Blk530's point, it's a standard Pb-acid replacement battery, and if it under charges this battery, I have a battery tender that I use, so it's simple to hook up, and I'll know if it's being under charged, and can keep it in a charged state.
As for registration, I found an indy that will do it for $70.00, but I think I'll just save the money and monitor the battery using my battery tender. I found that I could buy three batteries for what a BMW dealship would rip me off for if I went there.
Thanks, and I hope my story helps others that view this thread.