Hi there, I have the G1 data plan with unlimited=5G data. I am month to month and not interested in a contract.

I would like to get an unlocked Galaxy Nexus from Google and use it with my current plan, or cheaply modify the plan without a contract. Here's the phone in question:

http://www.google.com/nexus/#/galaxy

The page says that I will need a 4G plan.

What will happen if I put my current T-Mobile SIM for my G1 data plan into this phone. Will it be: a) no issue, b) a low-cost upgrade, c) the end of the world?

If (c), is it possible to disable 4G such that T-Mobile is OK with this phone w/o a plan change?