I have not done the iTX build but have 3 Phanteks cases here (Primo, Luxe, Pro) in this room and 2 of the 3 are water cooled. The videos should make everything clear. Dimitri put in two CLCs no issue. But there is nothing to be gained by hybrid cooling a 980 Ti.
1. The card throttles at 85C ... typical air cooled cards, fully overclocked, are in the mid 70s .. so whats the point ? If anything, the OC will be limited by the VRM cooling which is, at best on a hybrid, equal to an air cooled card ... oft it's worse.
2. Your CPU and GPU with CLC cooling will use a cheap aluminum rad, you will have a weak pump and no reservoir. You will have mixed metals in the loop which leads to galvanic corrosion. In order to overcome the weak pump and low transfer efficiency of the alum. rads, they must use high speed (noisy) fans.
3. Your paying $100 for the hybrid cooling + $100 for the CPU cooler. The Swiftech 240-X2 cools better, is all copper, has built in reservoir and is expandable to add a GFX card water block for $149. That water block will cost you $125 or so for a total investment of $275 ... so $75 more for all copper, no galvanic cell, much quieter.
Or as per the above Phanteks video, you could install a complete custom loop.
http://www.thinkcomputers.org/phanteks-enthoo-evolv-itx-watercooling-edition/
Typical loop might cost ya $450 if bought separately
$92 Radiator
http://www.frozencpu.com/products/16825/ex-rad-426/Alphacool_NexXxoS_UT60_Full_Copper_Dual_140mm_Radiator.html?tl=g30c95s930
$80 CPU Block
http://www.frozencpu.com/products/16252/ex-blc-1132/EK_Supremacy_EVO_Universal_CPU_Liquid_Cooling_Block_-_Nickel_CSQ_EK-Supremacy_EVO_-_Nickel_Original_CSQ.html?tl=g57c603s1907
$128 GPU Block
http://www.frozencpu.com/products/25574/ex-blc-1844/EK_Geforce_GTX_980_VGA_Liquid_Cooling_Block_-_Nickel_EK-FC980_GTX_-_Nickel.html?tl=g57c613s2313
$45 Reservoir
http://www.frozencpu.com/products/21671/ex-res-675/EK-MultiOption_RES_X3_110_-_Liquid_Cooling_Reservoir_-_White_Acetal_6_Total_Ports.html?tl=g57c615s1940
$105 PWM Pump
http://www.frozencpu.com/products/18221/ex-pmp-230/Swiftech_MCP655-PWM-DRIVE_12v_Water_Pump_-_PWM_Enabled_Full_Version.html?tl=c107s1802b33
Here's some entire kits for $240-$290 ... you'd need to add a WB for GPU for 4125 or so
http://www.frozencpu.com/products/25102/ex-wat-324/Alphacool_NexXxoS_Cool_Answer_240_D5XT_-_Complete_Kit.html?tl=g30c83s137
http://www.frozencpu.com/products/22394/ex-wat-285/Alphacool_NexXxoS_Cool_Answer_240mm_D5UT_-_Complete_Kit.html?tl=g30c83s137
http://www.frozencpu.com/products/18964/ex-wat-249/EK_L240_Complete_Dual_120mm_Liquid_Cooling_Kit_EK-KIT_L240.html?tl=g30c83s137
I haven't checked for compatibility w/ your components but the idea is just to show the small price difference between a hi performance, quiet cooling system versus a noisy CLC with low quality aluminum rads and weak pumps.
If you are new to water cooling, the Swiftech H240-X2 w/ a real, full cover water block (that cools the VRM) is your best option. The 240-X2 is very easy to install and, you can hold off buying the water block till the 1080s are bout when prices will drop a bit...and yes I have installed he H240-X