3. I have two ReplayTVs, and am not willing to give them up for a DirecTiVo or similar. So I need a DirecTV receiver that has serial input so I can control it with my ReplayTV. Do all DTV receivers have serial input? Most of them?

I am a ReplayTV owner who just recently had DirecTV installed. I was given Hughes SD-HBH receivers (no serial port) by the installer. I hadn't thought to ask for one that had serial control when I made the appointment, but I'm not disappointed. The IR Blaster does the job just fine. But consider that I don't watch live TV ever, and so I never experience the channel change delay.

On the other hand, a friend of mine who had DirecTV installed a few months ago received DirecTV branded model D10 receivers. These do have serial control, and it was recently that ReplayTV sent out a software update to support DirecTV's newer serial command set (called Serial APG). Before the update was released, he was using an adaptor designed by another ReplayTV owner for serial control.

So if you set out to choose a receiver that has a serial port, you should have no worries. But if you get your equipment from your installer and it doesn't, I'd still say give IR control a chance before replacing the receiver.