Hmm, I guess all of Asus's stuff has driver issues. Fun, I guess I'll skip the Asus sound cards. The driver issues I was talking about was a different issues specific to the Asus Maximus VI Impact Motherboard's sound card, something to do with not being able to utilize the amp all the way. I read about is somewhere, I forget where.
I think someone mentioned it before but have you considered the Schiit Magni? It's 100USD and very highly rated, once again, I don't own any of this (honestly too poor buy anything), but I did read a lot of the reviews and threads on the Magni (usually paired with the Schiit Modi DAC) along with some recommendations from people I personally know and the general consensus is that it is a really good Amp to have. No matter the level of Audiophile you are.
Just pulled the trigger on the Q701 - the waiting has begun
Schiit Magni seems to be getting good reviews in general, but I read that its synergy with Q701s is not optimal. I'll see how the Q701s will react to the Z and will review my options if I am not content with the results.