The horizontal seam on the wing is a poor engineering thing. There is really no need for it other than ease of assembly. The one thing I looked at when buying a new unit. If it had a seam there, I walked away. The other is the inside box area under the camper, behind the truck tail lights must be extremely well sealed because that is a pressure point for water when you drive in the sain, much like the nose of the cab over, only worse because all the spray from the truck wheels is hammering away under there and collecting in the corners.