SAS = Solid Axle Swap -- basically replaces the Nissan IFS up front with a solid axle from whatever you want to pull it from. Highly desireable (yet expensive) mod if you do a lot of off-roading, as the stock IFS doesn't deal well with being lifted and abused.
Although it doesn't seem like your trying to build a trail monster, so its probably not for you.
That being said, why restore a pathy to stock condition? More power to you if thats what you want to do, but if it were me I'd want to restore something a little bit more classic, while using the pathy to beat around the hills.
diffrent strokes for diffrent folks