Ahh. In the episode The Ultimate Computer, the Excalibur was destroyed by the Enterprise under the control of the M5 computer. I figure the same would have happened in the Mirror universe. The Empire would not waste a perfectly good ship. Just remove the dead crew and a coat of paint, you have a repaired ship. The primary hull is being readied to be connected to the new engineering section. In reality, I bought a extra saucer in case I screwed up the cutting up of the Constellation. As I bought the very expensive decal sheet, it seemed a waste not to get more use out of it.