Supernatural Durability is an exotic physical advantage (B89)
so if you already had these it would only cost 110
- The combo you want is Supernatural Durability  plus Fragile (Unnatural) [-50]. This lets you ignore more-or-less all wounding effects, and then suddenly fly apart at -HP.
in 2006 http://forums.sjgames.com/showpost.php?p=283281&postcount=6 also said same
- Were I designing them, they would have the inefficient but appropriate combo of Supernatural Durability and Fragile (Unnatural). Unfortunately, they were not designed by me. :/