autosleeper
100+ Head-Fier
Just get a balanced connection and be happy. Your ears will thanks you for it. The balanced jack is more dynamic sounding in all ranges. Soundstage is better including depth and width. More power translates to more punch at at the same volume level. If you going to pay for the ZX300, then a balanced out is madatory. Otherwise, I would just get the ZX100.
I actually don't really like the expansion to the soundstage I get through ZX300 balanced on my New Primacies. It's almost like the music is so diffuse it loses its 'centre' (I'm bad at wording these things). Could just be the degree of separation you get with the NPs tho - I need to try some other IEMs in balanced to compare.