Hello! I am looking to buy a used/refurbished Sony Xperia Z3 to replace my LG Leon. What's the procedure for doing that? Would it work if I just switch out the SIM card? I just read that there are different models of that phone set up for different carriers (https://en.wikipedia.org/wiki/Sony_Xperia_Z3#Variants), and I also heard that MetroPCS uses T-Mobile's network. Will a T-Mobile phone work? How about an unlocked phone? I am not very literate in technology, so I really appreciate your input! Thanks!