Well personally I don't listen to peoples opinions as much as peoples experiences
Personally I have the gtx 670 oc'd plus a Core i7 2700k OC'd to 4.6GHz on the single 80mm rad and temps are perfect and everything is near silent.
If you're only putting a single gpu on this rad I can't see how it wouldn't cool it efficiently.
TDP of my 670 is 170w
TDP of my 2700k is 95w
(mind you these tdps are non-oc)
I should've clarified those temps are in ambient of 23c.
On air cooling gpu hit 85c and cpu hit 78c, granted i'm in SFF so gpu would be slightly lower in a bigger case with a better air cooler.
In my experience and in the research I've done the fpi is not as good as an 80mm rad with slightly lower fpi.
Given the case you're using and the hardware I would use an alphacool monsta 120 x 80 in the front bottom bay area for the gpu and use a alphacool 120 x 60 in the back top for the cpu.
Alphacool really makes top of the line stuff for rads, but they can be a little pricey, you could use a monsta for the gpu and a cheaper 45 or 60 rad for the cpu of a different brand.
The black ice rads are nice I have used them in the past but they couldn't match the cooling I've done with the monsta rads - I was able to get same cooling as black ice with much less airflow, which means less noise too.
Good luck, let me know what you end up doing!