I am the original owner of this Mustang, from 1994 to 2013 it was driven in the winter on salted snowy roads. Since 2013 it has never been driven in the winter.
In 2014, when I had some work on the car, they said that my lower torque boxes looked bad. Now recently this year I was told about them again and they suggested that they should be welded. I have been keeping a close eye on them for the last ten years, and they have not changed much at all.
The picture where the torque box looks...
1994 Mustang Rear Lower Torque Boxes condition