The REF also boasts high-speed low-noise rectifiers and high-voltage film filter capacitors which increase the energy storage of the amp's power supply.  That means lower noise and better, sweeter sound.

The 24/96 Light Link is a practical solution to the problem of USB cable length.  If you're trying to run USB into a DAC but you need more than 15 feet or so, you're going to run into a big issue.  Namely, there's just aren't cords that'll do it.  The Light Link will take that signal, convert it to ST High Speed Glass-Fiber, which can handle the long runs.