Im looking to water cool my 7970 it isnt reference, so is it worth swapping it for a reference or waiting for the newer cards? (I did want to xfire two 7970's)
A non reference is the best normally. I would just wait for the new series, but you could crossfire, but if you are only doing 1080p a single 7970 is good enough, even for eyefinity if overclocked.
According to the latest info, Nvidia are going to release their 7xx cards towards the end of this month, there is still no solid info on when AMD will release theirs, but rumours suggest as late as November, even December.
Why don't you want to water-cool the non reference card? You want a full block? Why not just use a universal water block for the GPU and use heatsinks for your vram and mosfet