I have a friend who tryed to take off the old wallpaper and is also messing up the drywall. I myself have painted over wallpaper that was in good shape and never had a problem. What kind of Kilz would you use. They have more than one product out. I think the oil base one would be better. I want your thoughts on this. This guy does not have a lot of money to spare, and I was just trying to help him out on his project.