Blu Ray Plyr for Two-Channel Stereo RCA Outputs ?

The Oppo 103 does not have additional stereo analog outputs. You can use the FR and FL in stereo though.

Now I am sure you know that the 105 does have separate analog stereo outputs. I have a Cambridge Audio 751BD and it too has analog stereo outputs and it does a very fine job with stereo playback into my NAD T175HD pre/pro. A used Oppo 95 might be an alternative also.

Does using just the FR and FL channels cut the sound quality? That is, are those channels just sending out a narrow frequency band, or do those outputs send out the whole band?

From the Oppo 103 manual page 16.

x If your audio system offers only stereo audio inputs, or if you would like to connect a dedicated stereo
audio system in addition to the surround audio system which is already connected to the HDMI or
S/PDIF outputs, you can connect the dedicated stereo audio system to the FL (Front Left) and FR
(Front Right) terminals of the player.

x For the stereo outputs, if the audio system you are connecting to does not have surround speakers,
set the Down Mix option in the Setup Menu to Stereo. If the audio system has surround speakers
and Dolby Pro Logic or other surround audio decoding capabilities, set the down mix mode to “LT/RT”.
(For more information, refer to “Down Mix Mode” on page 68

Bill