That's the great thing about rumors......they're just rumors. If you want 4.2 on your phone, I'd suggest rooting it. There are several guides kicking around here. It's as simple as installing ODIN on your PC, installing the drivers from your phone (usually happens when you plug your phone into your PC, or you can install and/or verify the install with KIES. Then find a 4.2 ROM that's compatible with your device. T-Mobile ROMs are the same as Wind/Mobilicity/Videotron. You can stick with your familiar TouchWiz, or there are different options with AOKP, CyanogenMod and others. Take the time to read a few threads on the procedure and maybe look up a YouTube video or two so you can familliarize yourself with the process before you sit down to do it. Rooting your phone is as simple as one click with your mouse, once everything is installed and connected, and flashing the ROM really isn't that much more difficult.