So I have some 255/75/17 (32's) to be put on my rig. Currently I have the stock 15s which are around a 28" tire. So do I need an alignment with going up roughly 4 inches or should I be good?
Alignment is measured in degress of angle. A change in tire size doesn't change the angles of toe, camber, or caster, so there's no need for an alignment if what you have is in spec.
I am no expert but I would go ahead and get an alignment. I would think it would be a good idea especially if your tires are new. Just my .02 though. Good luck.