Why??? Flash a custom recovery and use it to root. Or - even better - flash sbdags modified and rooted stock rom, or - still better - flash CROMi-X 6.0.1
You can currently only root on an unlocked device. You can root on 4.2 or 4.3 it makes no difference. I made a flashable zip in the dev section But if you are going to do that go for CROMi-X 6.0.1 as berndblb says....