"Can I connect my airport express' optical output to stream the higher bit-rate files when it is connected via the ethernet port (not wireless)?"
No, only the Squeezebox Touch will do 96.
"As far as an upgraded DAC goes...I am looking at the Rega DAC, Moon 100D, and PS Audio Nuwave."
If you want a warm sound, the Rega or the Lampizator will do this. I recommend to use USB, but not the interfaces on these DACs. You will get much better results using the Off-Ramp 5 because it delivers lower jitter. Off-Ramp 5 will drive coax output to the DAC. Upgrading power supply and using a really good coax with the Off-Ramp 5 makes a big difference too.
Steve N.
Empirical Audio
No, only the Squeezebox Touch will do 96.
"As far as an upgraded DAC goes...I am looking at the Rega DAC, Moon 100D, and PS Audio Nuwave."
If you want a warm sound, the Rega or the Lampizator will do this. I recommend to use USB, but not the interfaces on these DACs. You will get much better results using the Off-Ramp 5 because it delivers lower jitter. Off-Ramp 5 will drive coax output to the DAC. Upgrading power supply and using a really good coax with the Off-Ramp 5 makes a big difference too.
Steve N.
Empirical Audio