Per a sales associate and the manager at my corporate store the 4G will not change through the contract. Additionally they confirmed that as long as you didn't change the data plan you would be grandfathers when getting a new subsidized phone as well. I know its not the same as in writing but a guy can hope in trust and a man's word right ? By the way this was after I had already gotten the phone so they didn't have anything to gain by telling me this.
Sent from my Thunderbolt
I'm pretty sure this is correct, because I just recently updated my aircard and still have unlimited data on it.
Sent from my Thunderbolt