2015 Fords won't rust but they will probably corrode like the tailgates on the expeditions. Alumimum is not a corrosion free material. Also had a buddy who had a Land Rover that had a alumimum tailgate that was corroding pretty badly. If your looking for something that resists rust I would stay away from Dodge unless they have improved a lot lately, as I see lots newer Dodges with quite a bit of rust especially over the rear wheel wells. Not too much you can do living in Minnesota to avoid rust, but I have seen some older vehicles with rust proofing stickers on the window and they actually seemed to be in much better shape then ones without. DieselDan