Well, neck, bracers and ring are pieces with the lowest statweigth. Then there is the trinket, that may or not be good for you. The numbers are easy, you get a +8 ilvl with 1500 valor, and you get a +x ilvl with 1250 on a low stat weight slot after 5.2. A +13 ilvl on a ring or neck may or may not be better than a +8 ilvl on a chest or helm.
Then again, you can replace chest or helm with normal pieces that same week, while the 522 will have to wait for heroic drops. I will go with 3000, or 2750/2500, depends on which week it drops.