I just rarely see customizing that is done to anywhere near the level of quality of the original watch (Bamford I'm looking at you).
Also, when I see customizing that basically destroys what made that particular watch great, I cringe.
Examples: DLC coating a nautilus. That watch is known for its mirror/satin polish and you did a half ass dlc coating over it? Or even when the bracelet of nautilus is bathed in diamonds. It's just feels like you could have done that on a different watch.
That's just me. No I would not mod my 5980/A1