The stock battery arrangement on the new precedent is the most efficient:
http://www.buggiesgonewild.com/attac...ompartment.jpg
You can also see the 2 new battery holders you need to purchase.
If you are not making your own 4ga cable set, make sure to use a stud to connect the new negative cable through the OBC.
http://www.buggiesgonewild.com/attac...g-obc-stud.jpg