I have owned the SFS-80 and very comfortably driven the Martin Logan SL3's... Actually that combo had magic that I have found hard to reproduce until throwing MUCH more money at the components. I have also heard the SL3's driven by the SFM-160's which was even better. I am not certain how they would do on the Quest Z, however I would opt for the SFM-160's if you can. I personally would avoid the Power 2 and Power 3 as the sonics changed quite a bit from a very musical amp to a much cooler amp, more neutral and less emotional/involving. Good luck.
