For inputs, it has a coaxial (Cable with TV Tuner), A composite, S-Video, and an Audio input on the back, and a composite and s-video input on the front.
For outputs it has Coaxial (Cable), Coaxial (Dolby Digital Audio), Composite, S-Video, and Component.
It does have a TV Tuner and Does record in Mono and Stereo.
I'm not sure about replacing the HDD.
So far I've recorded a couple of shows to the DVR and copied them to a DVD+R and a DVD+RW without any problems. The menus are basic and very easy to use.
As far a quality, there are 6 selections. I've only recorded in the 3 best selections without much dropoff in quality.