Are you having battery problems? If it were me, I'd see how well the current battery works before swapping it out just because anonymous Internet forum posters say you should. Save your money and change the battery when it becomes a problem.
Not everyone has the same experience that some here complain about; I'm still using the OE battery after 2 1/2 years and 40,000 miles. Never had a problem. It cranked right up even the times after it sat idle for almost 5 days in Montana last winter (single digit temperatures F) and almost 7 days in El Paso in June (triple digit temps F every afternoon). I sometimes use a power port to run my telescope for hours, and occasionally to run a 12V vacuum, with the radio on for the better part of an hour.
After the battery has been disconnected, the ECU wakes up in a default state and will have to re-learn its optimum settings, so performance may be degraded for a while. As far as I know, there is nothing you need to do but drive it, and it will come back up to snuff. There are a few things you will need to do, though, like re-initialize the power windows; there are instructions in your Owner's Manual under "Initialization of power window" or something like. I think the radio presets will remain, but the trip meters will reset to zero, so record their values before disconnecting the battery if you're using them to track something. There may be various vehicle customization odds and ends that get reset, too. Not sure.
This can be avoided by using a "keeper" voltage on the system. There are various ways to do this, but some just prefer to reset things afterward as simpler and safer.
Welcome, and enjoy your new car.
