Thanks geofelt, If anything i'll more then likely save my money and get the 670 2gb and slap some good blocks on em , 200 more cores isnt worth 200-/+ more
I would not even bother with water blocks at all.
There is an expense for water cooling, and the only good purpose is to be able to improve your OC.
Graphics card vendors are wise to this, and have binned their chips. The better chips are used in their factory overclocked versions so that they can be sold at a price premium.
Of course, you could get lucky.
But could a few % better OC make all that much difference?? Not likely.
Save the money and spend it where it will count more.