Follow the Gionee guide on their site for upgrading to KitKat, before you start the process, replace the recovery.img file in the ROM file you downloaded and extracted and replace it with a CWM or Carliv touch recovery file that works for the JB versions, this will give you a custom recovery (power button + up key when booting)
The 800Mb+ KitKat ROM update file has about 300mb of pure bloatware, unknown games etc.
Enable USB debugging
Download SuperSU from the playstore (we will use it to replace the chinese SU file later)
Download RootMaster (google it), this is an apk file probably made by the same chinese dev's who made Vroot
Make sure wifi is on, run RootMaster, all text is chinese, but the press to root button is english, it works, if it doesnt the first time try again (dont press anything else, it has a ton of crapware)
It should prompt that your phone is rooted, give it some time, it actually downloads a chinese version of SU
Now run SuperSU, it will replace the chinese version with the familiar english SuperSU ( although the chinese SU app with the lion emblem and chinese text will still be on your phone)
I recommend doing a full factory reset at this stage and using a root uninstaller app to remove all traces of this chinese RootMaster SU
The amigo system resources interferes with Xposed you can still get it to install the framework by first installing the Xposed apk and then going to the settings of the Xposed installer and checking the box "Disable resources API", this will mean GravityBox WILL fail.
Framaroot Doesn't work anymore
The best way to root this is to use Framaroot, Barahir exploit.
Although the Framaroot page on XDA does not list this as a compatible device (yet) it works really well.
All credits for Framaroot go to alephzain : here
This still works
BACKUP ROM WITH MTKTOOLS:
Download the awesome MTK Droid Root & Tools by rua1 from here
There are many detailed tutorials for using the actual tool ( I used v2.5.3) with detailed pictures etc., I wont reproduce them here, but before you read and follow the tutorials, make sure, your phone is rooted, you have the ADB drivers for your MT6582 chipset and the microsd card you put inside your phone is formatted inside the phone otherwise the backup will throw an error
Create & Install CWM:
Dev rua1's MTKTOOLS can also create a CWM image automatically from the boot.img that is created in the above step. There are detailed tutorials already available on many sites that show step by step how to do this. Installing CWM is up to you, either via Mobile Uncle Tools from the playstore (recommended) and the freshly minted CWM image or via SP Flash Tools using the Backup of ROM created with MTKTOOLS