I'm using Dirac 3, full $100 paid version, on my rig, ergo the NAD C658. Works great. Not sure I'm sold on what it does to the sound but I can tweak that later, I'm fairly new to it.
Also, you have to create your own Dirac account, it's not 'included' with NAD in the sense of auto-creating an account. How would anyone know who you are? Once you create your login it will fall into place, assuming you have some online / software fluency.