As per Doweyy's suggestion here:
Only a good price if you saved the Amex Offer down.
Worth noting - with the exception of the TGG Commercial deal, they have never been this cheap!
Also worth noting there is speculation that Sony is charging their suppliers more as a result of the popularity of the headphones, meaning the days of $320 eBay deals are likely few and far between.
Use live chat (closes at 10pm AEST) on Harvey Norman's website and use TGG's $395 less 10% off ($355.5) as a price match.
Note you can try your luck getting black headphones but my live chat guy would only price match on the Silver (TGG website only has silver).
10pm UPDATE: HN Live Chat closed, TGG deal still available until midnight.