A very good build.
Some thoughts:
1. Dominator/vengeance are marketing brands. Fancy heat spreaders sell.
But, they can impact some coolers. I do not know if that will be the case with the cm V8.
Regardless, the LPX low profile series will perform exactly the same.
Also, fast ram speeds come with higher latencies and higher voltages negating much of the performance benefits.
I think 1.2v 2400 speed will do just as well.
Here is a report on ram scaling.
http://www.silentpcreview.com/article1478-page1.html
2. sli gtx980ti needs only 750w.
http://www.realhardtechx.com/index_archivos/Page362.htm
I have no problem overprovisioning a PSU a bit. Say 20%.
It will run cooler, quieter, and more efficiently in the middle third of it's range.
A PSU will only use the wattage demanded of it, regardless of it's max capability.
I might suggest a Seasonic X850 which is a tier one unit on this list:
https://community.newegg.com/eggxpert/computer_hardware/f/135081/t/45344.aspx?Redirected=true
http://www.newegg.com/Product/Product.aspx?Item=N82E16817151102
3. SSD prices are down. Consider using a 500gb ssd and deferring on the hard drive until you actually need the bulk storage space.