Which Samsung Galaxy S III modem (radio / baseband) is the best for me? Different region have different Samsung Galaxy S3 modem because carrier, frequency band, topography, location and distance from cell tower are not the same. So you need to try Samsung Galaxy S3 modem yourself to find out the best Samsung Galaxy S3 modem for you. Using the correct modem will give your Samsung Galaxy S3 better signal coverage and battery life. By the way, these official Samsung Galaxy S3 modems are for GT-I9300 & GT-I9300T models only.
By the way, it is okay to install other region Samsung Galaxy S3 modem. But it will make your Samsung Galaxy S3 firmware as custom one. So you can’t use Samsung Kies to upgrade firmware anymore until you are back to stock firmware again.
Download official Samsung Galaxy S3 modem here.