If you get any edition, you will first have 6.31, the current public release. 6.4 is only a public beta. Beta releases have bugs in them, but 6.40.2 doesn't have much in the way of bugs (MED crashes when you pass 16 groups though, but otherwise nothing major). If you want Extra edition, you can get it. You can later upgrade your edition if you want (such as going to A6 Com, the edition I have). All you need to use 6.40.2 is to download the update in the updates and announcements forum and use the username and password provided to you when you buy 3DGS to access it. Do note that it does take some time to process orders and even more time if you go with mail delivery.