PC on a Gold, max dammage, nearly perfect chaos axe
Knight of Saitin
Change the mods and it's worth 500k++
Arya Nibelrund
Fortitude and sundering are the most valued upgrades.. i would try to sell it like that being an high end item the buyer will surely be able to afford the upgrades he wants; upgrading it yourself will cost you a little fortune and you probably won't get the money back.