I don't know for sure if there would be any difference, but either one will be somewhat of a PITA. Since you will be boxing it in, I would suggest you fill the box with insulation. I would look into possibly using the foam cans. This stuff expands, so you would have to allow for that, but it would help with the noise. I'd try to allow for the expansion so as not to have too much excess. You can trim off excess easily after it dries, just mask off walls, floors, etc. It's a bit messy to use, but latex gloves will help. Fiberglass insulation would also work pretty well, but not as well as the foam. Just some thoughts that might give you some ideas.