Default [Q] S4 Firmware and CSC from other region

Hello guys,

I would like to downgrade my i9505 with a stock ROM of April (preferrably XXUAME2) BUT due to reason we all know, I cannot find where to download it. However, I've managed to get a stock ROM from Brazil (ZTOAMDM) and I'm considering flashing it with this. My question is what is the impact of the different CSC as I live in a different region (EUROPE/GREECE), and if this change will eventually void my warranty.

I started a new thread because I coundn't clarify what's going on with CSC and regions from my previous search.

Thank you all in advance.