its all about your comfort levels and experience off road, i was blown away by my Xterra when i first bought it at what it can do, even with stock tires, i thought i was hurting it where in fact it eased through mud holes and over rocks...granted this article is using an OR model with the locker, but i still thought it was a good read, just goes to show how much the X truly is capable out of the showroom
http://members.ispwest.com/oldtrailmaster/xterra.htm