As noted above, the G91 will not accept a full resolution signal for SACD. That said, if you obtain a processor which can take the full resolution signal out from the Oppo as PCM, either the 103 or 105 will work, with the 105 supplying a better DAC for analog output at double the price. If the digital output is all you are concerned about, the 103 should offer the same performance.

James
NC1: 861v8, ID41, 218, 251(to outdoors), DSP8000SEUG, 7200SEC, DSP520 rears, Apple TV, DirecTV, Oppo BD103, QNAP251, Roon
NC2-M7005, Triad Silver Speakers,Acurus Amps

FL1: 861v4, ID40, 218, MS200, DSP8000SEs, DSP7200SEC, DSP5000s, DirecTv, AppleTv, OppoBD103, QNAP469, Roon
FL2: Marantz 7005, 251, M60s,60C,33s, Oppo BDP-93,MS200, Roon