So this one is a little specific and requires some effort, but works out being a solid deal if you have the Amex deal on your card.
Harvey Norman have MSI Gaming X RX 480 8GB for $426 + delivery.
They were more than happy to price-match the MSY price of $399 (see screenshot).
So with the Amex offer works out to be: $399 + $7.95 (delivery) - $100 Amex deal = $306.95
MSI Gaming X is meant to be one of the coolest/quietest RX 480's. Also with driver updates the RX 480 8GB is now very close to the GTX 1060 6GB in DX11 and beating it in DX12, but the 2 cards are basically even. If you want a GTX 1060 would be $333.95 after MSY price match and cash back delivered.
Also might qualify for Civ 6 promo with AMD. Asked Harvey Norman and they weren't sure so I wouldn't count on it.
Screenshot of Pricematch to MSY
+1 For effort in research and links provided op