Probably best to get it from DashDAQ Series II from Drew Technologies (make sure to buy the Ford signals). Reason being is that when you download updates, you're connecting to the dashdaq database and they individually package (on the fly) your update based on your serial, and so anything you've bought gets included in the download. If you buy from a third party, they may not get everything set up properly.
The AU currency is pretty strong right now, so wouldn't be a bad time to buy it.