Default [Q] Moving S4 from Verizon to iwireless/t-mobile

Hi,

I am thinking about moving my Galaxy S4 and moto RAZR from Verizon wireless to iwireless (a t-mobile affiliate). I understand that I need to unlock my phone but I am unable to find out if I move it to iwireless if I will still have 4G data. The iwireless sales rep said that I will still have voice and 2.5G service but couldn't tell me if I would still have 4G.

I was looking at this table I found on a site explaining how to unlock the phone but I don't know enough about the subject to make an informed decision.

Samsung Galaxy S4

Can someone confirm whether or not my Verizon S4 or RAZR can be unlocked to work with the iwireless/t-mobile 4G network?