We live in a world of day one DLC and $2.99 costume redesigns when it comes to "exclusive content" and all that sinister term entails, but every now and again something like "Drakengard 3" comes along and suddenly those incentives are as urgent as advertised.
If you fail to pre-order "Drakengard 3" before the 4th of March from the NA Square Enix Store you will miss out on the Japanese voice pack along with two other "waves" of yet unannounced downloadable content. For anyone looking forward to "Drakengard 3", you'll know that this is a pretty big deal.
For the most part, "Drakengard" games (including their cult sister spin-off "Nier") have had pretty decent English voice acting, but when presented with a chance like this it'd be foolish to pass it up. Let's not even mention how ridiculous original Japanese audio as an incentive is on its own, and just be glad that we're actually getting it. Something that was not made available with prior installments.
If Japanese voices aren't your thing and you're willing to the tread the waters of potentially hilariously bad voice acting, then go right ahead. For everyone else, be sure to nab it off the Square store before the deal ends early March. The remaining DLC incentives will be announced come March 4 and April 9 so stay tuned for those as well.
Keep in mind that the only way to get your hands on an actual physical copy of the game is by ordering online from Square Enix themselves and that Limited Collector Editions are already sold out.