Thank you for reaching out to us on our online Answers forum. I understand why you are contacting us with these questions and I would be glad to answer them for you.
The Slingbox will stream what ever quality you put into it up to 1080i. Since you have an SD cable box it will only do SD. If you get an HD cable box it will stream video out in HD.
The Slingbox has full control over you cable box using the IR blaster cables. So if you can normally access your DVR, set recordings, and other settings then you can do them with Slingbox.
Here are some links to check out:
I hope that helps out.
The Sling Media Moderation Team