I'm about to pull the trigger on this radio for mobile use, though I have some questions that I haven't really seen answered. 1. Does the APRS work "in the background" or do you have to have one of the "sides" of the radio dialed to the freq for it to work? 2. Will it work for ISS / SAT contacts with an Arrow? 3. Can the face plate attach to the body or does it have to be a remote install? 4. What is the real difference between DR and XDR? I know some are going to say that X radio is better and I should go with it instead. I really like Yaesu Products and want to stay with the brand. Thanks in advance.