Zenpunk brings up some very valid points in my opinion. The biggest tipoff is that there don't seem to be any plans to sell these in Japan. I asked a few Japanese distributors about them, and they said any info was basically nonexistent. If this truly was JVC's new flagship, they wouldn't be limiting it to sales in China only. Also like Zenpunk says, the 30% thing is most likely marketing. Sorry if that sounds pessimistic, but there's plenty of precedent for it. Just look at the box of the new Denon D7100: it says "tuned to be acoustically transparent and flat." Which is laughable quite frankly.
Speaking of precedent, JVC is known for releasing "new" models in different markets which are basically the same models only rebadged with a different alphanumeric designations. It wouldn't surprise me if the DX2000 is a DX1000 with some slight---albeit nice---changes (different pads, finish on the cups, etc.).
Variation does exist between units due to differing consistency standards. I've owned three different Edition 8s that all sounded discernibly different from one another. Other folks have encountered (and even measured) different sounding Beyerdynamic T1s and DT1350s. There was some controversy over whether the Sony MDR-7550 and EX800ST were the same earphones or not, with some people reporting differences. Yet it's more likely the 7550 is a rebadged EX800ST for western markets, as some 7550s even have the EX800ST name on their plugs and y-split. It's more likely the EX800ST just has stricter tolerances for variation since it's part of Sony's studio line.
Also it's entirely possible some of those positive changes on the DX2000 are also present on the DX1000 now. Fostex / Denon changed the original D7000 over time, refining and improving it.
