the card is covered at the back by a small metal shield, but it can be taken off from the screws It kinda sticks an inch at the back of the box.

on the Comcast brochure at the 8xx channels it shows a mark, which is explained underneath as "Additional HDTV equipment required. HDTV service may require certain level of services for some programming". So first part is the HD box, but I'm not sure about the second part.

I also ended up buying a samsung DVD player that can upconvert regular DVDs into full HD (1080p) - the only player said to be able to do that, as the others will do up to 1080i. Eh, not that my TV can display the P part, but surely there's big difference between watching a DVD over the AV inputs (480i) and over the HDMI input (1080p/i). I was kind of sceptical about this upconversion thing, but now I can asure anyone that it's well worth it.