I have the offroad package. There aren't any suspension differences except for shocks absorbers. For the 315s you will need to crank the TBars quite a bit to clear them. Probably 2+ inches.
Yes, you will need an alignment after you crank them. It will throw off the caster and toe in of your fronts.
So far as rubbing goes, members that have them report that they do not rub, however, in a full articulated situation at full lock I suspect there to be some rub. For most driving conditions you should be alright. You will also need to have you speedometer recalibrated after the larger tires are installed.