Hello and welcome to our AndroidForums!
While its entirely possible that nothing more than a different language will be presented to you in the various text/screens, etc., there is also the possibility that there are differences in the ROM that might cause you problems.
For example, if your country's version of the device and ROM include specifics related to your phone's hardware--especially something like the cell radio--that could indeed cause you problems.
There are probably very good reasons that the carriers have and release different ROMs for different countries--in fact it certainly costs them time, money, and effort to so--so it's likely not a good idea to flash a ROM not meant for your country/device.
Cheers!
