I want to get another HD receiver to replace one of my SD ones. Can I do that myself? Buy one at Best Buy or on-line as opposed to having a techie come out to do it?

I know they seem to like their own installers.

Also, if I get a receiver without a card can I just swap the one out that is currently in the SD recevier into the HD one?

There's nothing wrong with installing it yourself - they offer the professional install to make sure it's done right and you get TV without calling in too often to complain about a crappy install. If you have an existing install, you should be able to do it yourself with a new receiver, but to be 100% sure, you would need to call & ask a CSR. They will need information from the box to activate it for you so that you can receive signals.