I don't see any difference in the potential wear-ability of parts with either method of widening the stance, it creates the same longer moment arm. I added 1.5" billet aluminum spacers on my 1989. I read an article on the rollover lawsuits, and it said the engineers recommended widening the stance my 3 inches, but Ford didn't want to do it. So I just listened to the engineers. There was a noticeable difference. But it just pointed out the need for new sway bar bushings. I went with Poly.
Now my springs feel too soft and I'd like to upgrade with some stiffer springs all around. Trying to find out if Explorer or Ranger springs will be stiffer, and by how much. Anyone know?