I will be using my favorite headphone Denon D5000 (mod with Beyerdynamic DT880 pad to tighten the bass) with the headphone amplifier. As for speakers, I will be using Virtue Audio's Virtue ONE class T amplifier to drive a pair of Klipsch RB-51 satellite speaker and an active Boston Acoustic XB4 subwoofer. Probably Line Output (rather than DAC Output) of FUN will be used to feed line input of the Virtue ONE power amplifier.
On another subject, I asked Kingwa if they were planning to add new modules and he said that he might add in the future the PCM1704UK dac module if there is enough demand for the FUN. The only weakness I found in the DAC is the slight "digitis" that is common to all delta sigma dac chips I have listened to (cd players and dacs costing to up to $5000). If he can provide the PCM1704UK chip in an entry level it would be very very interesting.