If the unit is new you will have no problems. If it is used. You will have to call DTV and purchase a NEW D2 Card for the unit, even if the unit comes with the old card. DTV will not longer re-sub a used card. The card cost $20 for 2nd day FedEx shipping. You will have 10 days to active the card before it will go dead. If the unit is still subed by the current owner, you will have all kinds of trouble. DTV will not, and can not under their current computer system actovate a unit that is currently active under another account.
I just purchased a used unit, and had to go through the whole process. I had to email the seller and get him to de-activate the unit. I order a new card from DTV for $20. I am watching tv on it today.
I would suggest that you buy a new unit. You should have no problems.