I wish Kingwa would make use of the digital volume control functionality on the ES9018. This would be quite a simple inclusion and would make the value proposition of his Sabre DACs so much better since the user could lose his preamp altogether. I'm confident the analog output stages are beefy enough to fully drive amps directly even over long interconnects. Compare the features of the W4S DAC2 in this respect.
Moreover, the lack of a proper async USB 24/192 input is starting to feel a bit like legacy technology now. I'm not saying that Kingwa should slap on a TE7022 chip solution just to add USB functionality but to work out a proper solution that could be housed onboard, even if that means licensing technology from M2Tech or the like (again compare the W4S).
I know Kingwa has been struggling with getting the USB/I2S interface to work with the ES9018 but perhaps he could team up with jkeny (John) to equip the DACs with his latest USB/I2S solution (https://sites.google.com/site/hifacemods/home/announcements/hifacei2s) or I may perhaps just buy the basic DIY unit with the connector and PSU packs and ship to Kingwas for custom inclusion in the DAC8 