In my experience, both the Westone 2's and the Westone 3's sound really good with the sflo2. The sound from each is different for me, as the Westone 2's seem to bring out the higher frequencies (while still allowing nice bass) a bit more than the Westone 3's, but to me both are quite well suited for the sflo2. So if you like a little "brighter sound", you might want to consider the Westone 2's. I also think that the UE triple fi 10's and M-audio ie 30's do quite well with the sflo2, and analogous to the Westones, the M-audio ie 30's sound a bit brighter than the UE triple fi's. I have a set of recabled etymotic ER-4P's (recabled with Apuresound cables), but the HO unfortunately does not drive these well (can't get enough sound volume). I have recently oredered a headphone amp, so I can try the recabled ety's with the LO. The only IEM's so far that I haven't liked with the sflo2 has been the Future Sonics Atrio; these IEMs bring out too much bass, and not enough treble for me. But I have not tried to adjust the EQ for any of them, I listen to the sflo2 with Normal setting.