First you should tried it update by SEUS ( Sony Ericsson update service ). You can download instalation program from here.
By some phones SEUS updates the CID to a higher by himself, but if by you doesn`t you must it itself.
No, you can upgrade with any firmware that you want, only the cid number is important that it`s same or higher.Also, the NetworK is "VFE_LIVE_2", is this mean i have to upgrade it with a "VFE_LIVE_2" firmware?
Nice day