Default [Q] Firmware upgrade


I own a rooted, stock ROM N9005. I live in Serbia, and was wondering if it is safe to download and flash the new firmware intended for Singapore (N9005DXUENE4), or should I stick strictly to firmwares intended for my area?

What do you wise people advise?

At the moment, I have some problems with wi-fi connectivity (connection unstable) and none of the methods I found on the Internet helped. I was kinda hoping that the firmware flash will fix it finally, along with some battery and stability improvements.

Also, I have a custom AEL kernel. Will that get in the way of firmware update?

Thank you.