The GX300 records whatever two-channel program you input (Dolby, DTS...). It outputs digital pcm, or Dolby/DTS with its internal decoders.
Before you buy it, check the DVD loading speed. My post of yesterday:
"...the damned thing takes a long time to load a pre-recorded DVD. I mean about 2 - 3 minutes from the time I drop a DVD onto the tray until it's ready to play. In fact, sinply pressing the 'tray open' command takes about 30 seconds before the tray opens."
I don't know if this is normal (the purpose of my post was asking), but if it is, you'll likely become as impatient and frustrated as I am with it. Otherwise, it's a gem.