Can I achieve root without re-flashing the device? if not how can I backup my devices current configuration including apps etc?
You need to flash the SuperSU zip via recovery to have root access. Flashing supersu doesn't wipe your device's configuration or files. Unlocking the bootloader wipes it!
Use Helium to backup your apps when you're unrooted. Once you have root access, I would recommend using Titanium Backup!
When would I need to unlock the bootloader? only if I changed to a custome ROM right?
When would I need to unlock the bootloader? only if I changed to a custome ROM right?