Default [Q] Root on Samsung Galaxy s3 i9300 running stock 4.3

Hello everybody, I know this must be some kind of repetitive question here but you know I'd like to be absolutely sure of what I'm doing before rooting my Samsung galaxy s3 i9300. As you know now android 4.3 has been relased so I have the full stock 4.3 rom now (if it is useful it's an italian model, no brand, I'll post the screenshot with kernel and build info). I'm not pretty much experienced, but I'd like to fix some things on my phone such as a bug with the clipboard (device reboots when I click it), eliminate advertisement and some useless stock apps, create a full backup of the phone, modify touchwiz OOM to 1 to prevent it redrawing so often, and deny permissions of autostart at boot on certain apps.
Still, I don't want to lose my data (so evitate hard reset) and I don't want to install any custom rom to be sure I can still receive OTA updates normally. What's the simplest procedure I have to follow?
Another thing I forgot, I obviously want to be sure I can unroot and get warranty back in case of necessity, does triangle away work on android 4.3?
Attached Thumbnails
Click image for larger version

Name:	Screenshot_2013-12-31-00-31-31.png
Views:	706
Size:	146.5 KB
ID:	2484398