I have been looking at all the new DACs for one to mod but until now have not seen anything worthwhile.  The Gustard X20 looks like the real deal.  $870 delivered from China with 2 ESS DACs in dual mono mode (8 parallel DACs per channel) and discrete output stages......it looks like a $3500 product and according to the guy in the below link beats the Schiit Yggdrasil and the Auralic Vega.....these two heavy hitter DACs ($2300 and $3500) are seriously respected DACs in their price range. This DAC can handle double speed DSD via USB and Quad speed DSD via I2S as well as the usual 32/384 PCM.  It has a digital volume control with remote so could be used to directly drive an amp.  Check out this link: 
Gustard X20 DAC mods

Here is a tentative list of things I want to do to this DAC. 

1. Change the fuse to better one
2. Change steel hardware to non magnetic hardware
3. Add WA Quantum chips to DACs and capacitors
4. Add several Mad Scientist Magic Tubes
5. Change three clocks to low jitter Femto clocks.
6. Change the ouput stage to a single discrete stage per phase (4 total).
7.  Damp parts.

More stuff could be done but these things will take it to another whole level.  This modded DAC may compete with $10,000 DACs.  It looks like about $450 in my cost in parts and another $400 for labor.  The first person to send me a Gustard for modding will get it for $100 labor plus parts and return shipping .  It should not take more than 3 weeks to work up the mod....pretty simple really....but I want to try 3 different output stages.

Here is a link to where you can buy it:
Another link where you can buy it and more pics :