This company may have an adapter that would convert the BoseLink 9-pin connector to RCA's, but I would just use the headphone out.
http://www.4electronicwarehouse.com/c/boselink
Both outputs should carry the same analog audio, so the sound quality would be the same. The headphone jack probably has variable output, so you will need to watch the volume level on the Wave radio...probably set it at 25-30% for best results.
http://www.4electronicwarehouse.com/c/boselink
Both outputs should carry the same analog audio, so the sound quality would be the same. The headphone jack probably has variable output, so you will need to watch the volume level on the Wave radio...probably set it at 25-30% for best results.