Which CP & CSC code choose to install stock rom Galaxy S3 i9300

I am installing stock rom because of get warranty back (now i am running Archidroid). I don't know which firmware I should choose. My actual region code is **XEF** (stock recovery is saying that it's XEF. Archidroid is saying **I9300ARCHIDROIDARCHIDROID** but I live in Czech Republic so It should be **XEZ**. Than, I don't know which *CP* number i should choose.. My actual is **I9300XXUGNA8** which is *Uzbekistan or Kazakhstan* (wtf? :D). What will happen when I flash stock firmware with **XEZ** (csc) and **I9300XXUGND5** (CP)? Thank you for your help. I am noob. I was googling and I found just what is AP, CP and CSC. But not what happen when I change it. *I have international version of Galaxy S3 (GT-i9300)* Thank you in advance