?
Batteries can be deep cycle, but entire cars? Not so much...
Even if the OEM battery was deep cycle (and I don't think it is), that wouldn't mean that it would maintain its charge for a longer period of time...it would just mean that you wouldn't toast the battery if you drained the crap out of it.
That said, if you leave it for extended periods of time without driving it, then you either need a battery tender or to put it in hibernation mode. I prefer a tender...I actually have a battery tender pigtail hooked directly to the battery terminals in the rear of the car. When I'm done driving it, all I have to do is reach through the bumper, grab the pigtail, and hook it up to the battery tender. Simple, effective, and I don't even have to pop the trunk or hood to keep the battery topped up.