I realize that uni-body cars are engineered to be structurally strong and rigid, but I would assume that over time the body might become a bit 'loose'. During the restoration process are there any areas that should be inspected or considered? Can/ should any additional welding be done to enhance or correct the original factory welds? Even if not necessary, is there an advantage to adding any additional material to enhance or improve the factory structure? Any areas that are prone to weakness?