I just checked updates and i do believe that the gingerbread update is open to the public now.
These questions have been answered many times.
z4root uses a Froyo-specific exploit. It doesn't work on Gingerbread.
ClockworkMod recovery works.
2.4.x SBF can be flashed, the bootloader was not altered.
Sony LT25i “Tsubasa”, stock, rooted, locked bootloader [Android 4.1.2 “Jelly Bean”].
Maximum speed witnessed over LTE: 98.2 Mbps down / 48.5 Mbps up; Average speed over LTE: 72.9 Mbps down / 45.7 Mbps up.