That sounds very appealing from a character standpoint.  Will you be wanting to change the effects of the lower level Ancient Helean Armor as well?  You should also clarify whether the damage reduction granted by this armor is bypassed by anything such as magic, alchemy, damage type (slashing, blunt, piercing) or types of metal.  I'm imagining you're wanting it to be a flat damage resistance that would reduce all incoming damage by the amount granted by the armor.