Hello there! I have the Tmobile $30 a month prepaid plan (includes unlimited data that starts at 4G). If I buy an unlocked iPhone 4s, can I just stick in my sim card and start iPhoning? Also, will I get the 4G speeds that come with my plan? I read this article "49 Cities Where T-Mobile iPhone Users Can Expect Fast Speeds" and I live in one of those cities. I'm just not sure because I hear other things as well (ex: 4G only works with iPhone 5). Please help a fellow pal in need! Here's the link to the article I mentioned: http://www.pcmag.com/article2/0,2817,2416666,00.asp Thanks!