You can buy naza m-lite with gps for 130 eur and upgrade it with this tool to 240 eur naza v2.
Both nazas have same hardware, but different firmware.You can also downgrade it to original firmware, so there is no problem with warranty.
Follow this instructions:
http://naza-upgrade.com/
Tip:
When you try to upgrade it make sure you do not have skype or other messenger running in background on your pc. You will use naza v2 assistant after upgrade.
After some testing I’m very pleased with upgrade.