There are no difference in PQ between 7000 and 8000.
C series can be hacked by pressing few buttons and reveal all hidden menus only 8000 have.
It's just that 8000 has shiny bezel if 7000 is unlocked.
And I'm not sure why you would get C series when there is D series on the market for more than 6 months now. E series will come out in few months...