its true, the doors are made in a unique process, specialist equipment is required for the welding, a friend of mine has been the the vendor that supplies MINI with doors. Something to do with the angles and curviture of the door, its all very technical and apparently they are the only ones that can do it so I am told. So a new skin cannot just be bodyshop replaced, its a whole door to replace or repair.
Make us feel special about our cars and parts knowing that they are so hightech using the latest technology, well till we need replace parts
