Sent an email to Kingwa for new a driver version... ;)
I listen the DI-V3 at occasional times but the Master 7 with the new firmware sounds good. I can't provide a detailed comparison because I have also exchanged tubes in my headphone amp. The new firmware 2014V2 and drivers work flawlessly in my DI-V3 (WIN 8.1). Try it...
For those curious about installing the new 2014 firmware and driver on the DI-V3, I have installed them on the DI-V3. It works although playback is only available via WASAPI and not through ASIO for now. Kingwa mentioned in an email that the ASIO only works in 32bit output so not applicable to the DI-V3 which can only output 24bit for SPDIF.
The sound is definitely an improvement over earlier firmwares and drivers with better separations, soundstage depth and a balanced improvement at both ends of the extensions. It's a really nice sonic improvement.
I did try using the earlier USB32 v2 driver which allowed me to use ASIO in 24bit mode. Although there is a slight improvement in the trebles, the bass seems to sound dry and lacking. Can't compare with the sonics with the actual 2014 drivers.
Would be really worthwhile to wait for the new firmware and drivers for the DI-V3.