I recently took a job in Germany, I have an AT&T unlocked iPhone 5. Will I be able to use it with T-Mobile or O2? If so can I use LTE on these carriers? Same with the 4th Gen iPad, I'm thinking about getting on but I don't know of I need to get an AT&T or Verizon model, or would it be better sell my phone and get one in Germany.. If I go that route, are the phones unlocked?