OPPO 981 versus 983 for Audio Playback only

I'm looking at buying an OPPO for playback of my CD/SACD and HDCD encoded discs (HDCD are mainly Grateful Dead discs). I'm not planning to use the player for Video now or in the future so only interested in the audio sound differences between the disc players. What is the difference in sound between the 981 and 983 players and does it warrant the extra dollars that the 983 costs for audio playback???

I recognize that this is a difficult question and sound quality is somewhat subjective, but would appreciate any of your thoughts.