if you don't drop your diff the odds of your boots surviving are slim, and i wouldn't be surprised to see the CV's follow, no personal experience, just my thoughts
What are we talking about, 2nd gen 4Runner or 2nd gen pickup or 2nd gen Tacoma? They all have a different front end.
Early IFS you should be ok at 1.5 inches. Go much farther and you'll start shredding boots, but the CV will hold up as long as you keep rebooting it. A diff drop will help. The next IFS with coilovers, guys get 2.5 to 3 inches and don't go through boots or CV shafts too fast, but definitely don't do a diff drop - it puts the diff on an angle and there's a question if it gets oiled correctly that way. Second gen Tacoma I have no idea.