I don't recommend using the 2.0 as a preamp. Despite TacT's claims to the contrary, you start loosing resolution when you control the volume via the TacT. For high settings, say 85.0-99.9, it sounds fine. But when you start going below 85, the sound starts getting lifeless. My buddy with a 2.0 was using it as a preamp, but once I convinced him to try putting his analog preamp back in the system, he has never gone back.
Also, you have excellent equipment, so you may want to consider an external DAC. The DAC card for the 2.0 is good for the money, but to my ears it is not in the league of your other components.
The 2.0 is to my mind the best component available for home audio. There is simply nothing that makes more of an improvement for less money. But it does take a big commitment from the owner. To get the best from it, you will need to spend time trying different curves and learning about it. At first you may be frustrated. But hang in there - in time you will be very richly rewarded.