Samsung Galaxy S3 — S. Korean Galaxy S3

Hi all.
I am a complete noob regarding all this so please forgive my ignorance of all things android....
I have been offered a Samsung Galaxy S3 at a very attractive price by a friend who bought it but can't get on with it.
The only thing is, it is a Korean version. It's no problem to change the language but is it possible to wipe the fw and install european fw?
I believe that as a Korean telecoms icon appears on start up that it's not possible for it to update automatically.
I have been told that it's not possible to alter these Korean phones but I'm not sure if that's correct or not.
Any help and advice would be gratefully received before I make the purchase.
Thanks in advance.

I don't think it's locked to a carrier as I have typed *#1234# and everything comes up as 'off' so that neabs unlocked I take it?
The model number though is SHW-M440S so I'm concerned about trying to install a firmware for I9300 model in case it all goes wrong and I'm left with a useless phone.
I connected to Kies and it stated that there was an updated FW available but it is the Korean version again.
I don't understand anything about ROM's and Kernels so I'm unsure whether to give it a go or not. I updtaed the FW on my old Samsung Tocco with no problems but this is a completely different (and more expensive) animal!
I was hoping someone on here had already had the same issues and could advise before I do something I will regret.

Thank you.
Do you think that I will need to root it before installing the new firmware?
What would happen if I just went ahead and installed the I9300 firmware on the phone as it is right now?

Hi, I never actually tried it.
I just use the phone in its standard form and it's fine.
The only issues I sometimes have are that I can't remove the Korean Apps and the sms is limited to 40 characters.
If you have a go at yours though I'd be interested to hear how you get on, thanks.