Firmware Differences - Galaxy S III Q&A, Help & Troubleshooting

Hey all,
I currently own a white 16GB GT-I9300 with the stock ICS Vodafone New Zealand ROM loaded on it, the latest version available from my carrier. The phone was bought from Vodafone New Zealand itself and came with VFNZ firmware. My mother has fallen in love with the phone after trying it out once P) so I'm going to give her my marble white GT-I9300 to replace her iPhone 3GS and buy a blue GT-I9300 for myself.
The question I have is regarding the ROMs/firmware available for the new GT-I9300. The blue one I plan on purchasing is not direct from my local carrier, and it is listed as a parallel import, so I assume it'll either come pre-loaded with a ROM from a different foreign carrier, or the unbranded ROM.
I'd prefer to have the Vodafone NZ ROM on the device since it has all the carrier and access point settings, and I assume since this new blue model will also be the (international) GT-I9300 model, I am safe to flash the Vodafone NZ firmware onto it? I want definite confirmation if possible, before I go ahead and brick a new $860 phone.
I'm very new to Android (the GT-I9300is my first Android phone) and have only flashed+rooted twice, with stock firmwares using ODIN. I noticed each different carrier ROM has a differing set of numbers (PDA..? something else as well?), which I don't remember the names of. Does this have any effect on what ROMs my device is tied to using?
Thanks for any help.

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PDA refers to the build version of the software/firmware
Phone refers to the baseband/modem version
CSC is the consumer software customisation and is specific to geographical region and carriers. It contains the software packages specific to that region, carrier branding and also APN settings for data connection, MMS etc for your service provider.
CSC has nothing to do with what languages the firmware supports and it will not add keyboard language support either.
.PIT refers to the partition information table you only need it if you screw up your partition table or if the firmware specifically requires it because of a change in the partition table layout. It's very likely you may never have to use this.
If the package only contains one .tar archive then it will have everything, pda+phone+csc, in the one file.
If it has multiple .tar archive then:
The .tar with modem in the name is the phone/baseband bit of the package
.tar with csc/multi-csc in the name is the csc bit of the package
.tar with code/PDA in the name is the PDA part of the firmware package
If this is the case you will need to put these .tar archives in the specific areas of Odin to flash the update. Refer to the images below.
You do not need to root or unroot the device to update the firmware.
Please ensure that KIES is closed and not running in the system tray! Kies doesn't like Odin, it's like the big brother who's always jealous that his little brother is getting to flash all the phones so he starts to flash block.
Regarding change logs. Samsung thinks firmware should be like a box of chocolates, you never know what you’re gonna get and that all a big part of the surprise user experience program so they don't publish any change logs.
Get Odin v3.04 from here: Download https://androidfirmwares.net/Tools/Download/8
Just extract the Odin folder.
You will also need to install the Samsung USB drivers for the device if you haven't installed KIES. Get them from here: Download
Just install like any Windows program....
Stock Firmwares
http://www.sammobile.com/firmware/
Samsung Letter Code
CE---> Belgium, Luxembourg, Netherlands
DC---> Thailand
DD---> India
DX---> Indonesia, Malaysia, Philippines, Singapore, Vietnam
DZ---> Malaysia, Singapore
JA---> South Africa
JC---> Algeria, Morocco, Nigeria, South Africa, Tunisia
JP---> Arabic, Algeria, Egypt, Iran, Iraq, Kuwait, Morocco, Nigeria, Oman, Pakistan, Saudi Arabia, Syria
JV---> Tunisia, Turkey
UG---> North America
UH---> Latin America, The Caribbean
XE---> Bulgaria, Estonia, Kazakhstan, Latvia, Lithuania, Russia, Ukraine
XX---> Austria, Belgium, France, Germany, Hungary, United Kingdom
XW---> Austria, Belgium, France, Germany, Hungary, Italy, Nordic, Spain, United Kingdom
ZC---> China, Hong Kong
ZH---> Hong Kong
ZS---> China, Hong Kong
ZT---> Taiwan

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You can flash whatever firmware you want, go to samfirmware.com and you can search by phone model, country, carrier etc.
Most ROMs will come in one package which will be like "xxxxx/xxxxxx/xxxxx.tar.md5" if it all comes in one package you put it in the PDA section of Odin and flash it.
Sent from my GT-I9300 using xda premium