I cannot imagine any real world advantage by going to 4 in SLI.
Water Cooling is a process and reading up on it is strongly recommended. It is more complicated than a closed loop cooler, but not anything that is too difficult. PATIENCE is key with water cooling. I started with a XSPC kit and went from there. Research which configurations will fit your needs and case are important. I read lots of reviews on all in one kits and watched a number of youtube videos for ideas. I would probably start with just cooling the cpu with a kit and then branch out from there. EK and XS-PC make some good stuff.
 
1500W PSU is what I would recommend for 3 or 4 cards. I have a 1200W for 2 video cards and water cooling setup.
 
KingPin and Classified models come with better components will help you achieve higher overclocks.

Are you about "now" or "later"?  In other words, how long do you intend to keep the system without upgrading?
 
Most people that tell will you that 4-way SLI has no point are speaking from the perspective of "now", i.e. the sheer number of reviews with year 2014 game titles don't show gain adding the 4th card in SLI.  So they will suggest you stick with 3-way SLI and enjoy.
 
But most people don't think about "later" when games get more intense they will need more rendering power, they just assume you'll upgrade to a faster set of a few cards that ironically perform the same as 4-way SLI GTX980 does now-- so why go through the upgrade later?  I've never understood the logic of only getting what you need, it forces you to upgrade often.  So if you overkill now, you add years, what's wrong with that?  It isn't like time stops and no games will ever get more intense.
  
Also, about your CPU, games still don't use more than the four cores in a quad-core, and quad-cores have been around for nine years.  Maybe in a few more years, games will start to need 6-cores, but by the time they used 8-cores, you would have replaced your computer several times.  If you have a newborn now he/she will be in middle school by the time you run into games that need 8-core processing.  People will always recommend only get that thing if you do more than game; remember, the LGA2011 platform originated as Intel's server platform, it has way too much ability compared to mainstream and is rebranded for enthusiast use.  Not bad for the money, really.

Gaming on a single Qnix 2710 with 3 980's is overkill. I would look into 4K gaming with GSync to properly push 3 x 980's or 3 x Kingpin's.
 
Any of the below kits from XS-PC can get you started. The nice thing about looking at these, is that you get an idea of what you have to have for your loop. Once you start learning more about it, you may want to put your own setup together.
 
http://www.frozencpu.com/cat/l3/g59/c683/s2176/list/p1/XSPC_Products-XSPC_Water_Cooling_Kits-XSPC_Kits_480-Page1.html
 
Here are some EK kits as well.
 
http://www.frozencpu.com/cat/l3/g57/c607/s1949/list/p1/EK_Products-EK_Water_Cooling_Kits-EK_Kits_-_360-Page1.html
 
 
Here are the main two sites where I have purchased my watercooling gear.
 
www.frozencpu.com
www.performance-pcs.com
You can use OCN at the checkout for a 5% discount :) for these sites
 
Other sites
 
www.amazon.com
www.sidewindercomputers.com
 
 
EDIT.. I will add that it seems that watercooling will never be complete until you are probably ready to do a complete upgrade :)  There are just so many little things that come to mind after you do your initial setup. I wanted to do watercooling for a couple of years before I jumped in and now I love it. I don't mind spending money that has nothing to do with performance. I just like that way something looks or it might be more efficient if I do this instead.
 
I would strongly suggest sticking with a setup that you can upgrade later and begin with just the cpu. Once you have that, you can tackle the gpu's. You will probably end up doing two separate loops anyway with 3 KINGPINS :)
 
 
Here is a build log I looked at for awhile.
 
http://www.overclock.net/t/1380883/build-log-900csq-900d-maxed-out-everything-watercooled-acrylic-tubing
 
There are other build logs out there as well.
 Here is mine. not nearly as good, but maybe you can learn something from it.
 
http://forums.evga.com/First-H2O-build-log-900D-XSPC-Kit-360-Rad-added-VRM-block-and-140-Rad-added-more-m2192539.aspx
 
 

Thanks for the info guys, movieman: do you know if these sites offer like a set deal if u tell then what I have and they put together and send?

Also, your opinion on waiting on the kingpins or just installing 2 of the 980s as mentioned above. What would be the choice, would a getting into w as ten cooling/over clocking noob benefit from waiting on the kingpins or just rock the 980s that I have now (I say this because they're unopened and can be returned easy).

Scarlet-Tech
2 cards, unless you are benchmarking. 2 will max just about everything out or put it well over the fps/refresh rate capable of your monitor, unless you speak of terribly optimized, extremely demanding games. No point in spending an extra 500+ for something you literally can't see.

If you ABSOLUTELY have to spend the money on 3, then do so, but it doesn't improve enough to benefit and will mostly be bragging rights only.

 
Scarlet-Tech:  I noticed you have a similar setup as far as processor (mine is a 5930), same MB.  I was wondering if you had a list of stuff you used for water cooling loops etc.  I don't want to pay 4-5 shipping charges on an oops I forgot.  I know yours says custom but maybe you started with a kit and added to???  Any help would be appreciated, thanks. Oh, and I'm using 900D case.