If you want to test the Brazil rom you can. I have been on it for a week and haven't noticed anything stopping it except for not being able to root.
Here is the kdz file needed:
You install it by this method:
◘►◘►[FLASH + ROMS][v20B.KDZ] KDZ Files on WINDOWS 7 (64) & XP + Download◄◘◄◘ - xda-developers
You may need to wipe data by going into recovery afterwards:
Power + Vol Down
Make sure you add at&t apn after install to get working data.