I just got the Oppo 103 for DVD/BlueRay playback, and the sound quality is superb. It has RCA outs for a 2-channel hookup (as well as 5 channel hookup), which is what I use.
My own feeling is that, where CD players are concerned, you can hit the upper limit on sound quality at a relatively low price point--heresy for some, I know. Could the discerning ear hear the difference b/t a 103 and the 105? I doubt it. In fact, I doubt discernible sound differences between my old Sony $99 dvd player and the Oppo 103 that replaced it. I only got the Oppo for it's build quality and versatility--not only playback variety, but convenience features.