I think you're stretching a bit.
With both the 103 and 105, you get what you pay for. Both are AMAZING values.
With that said, the 105 is close to double the price of the 103 for one primary reason : Increased audio performance all around. Oppo states this. Many reviews do also. THIS is why it costs more.
The 103, while no slouch, was built for video-philes who will likely use external audio processing anyway.