You should also look into the iFi iCan. I use it more often then the M-stage.
I like it because it's a desktop amp but with has two levels of quality sub-bass boost as well as a soundstage boosting switch, which surprisingly doesn't sound gimmicky and works pretty well. Since the bass boost is at the amp-level it's clean and causes zero distortion, unlike bass boosting with a mixamp/dss and double amping which can clip the signal and distort.
The iCan isn't as powerful as the asgard, but it should be plenty for the X1. It also has very low output impedance (<0.5 ohms) so very good damping factor and what not...
Here are some more of my impressions on the soundstage boost:
Here's an article on it's bass boost: