SiggeLund :
Well the reference design has the upside that all heat is blown out the back of the case. When the closed loop watercooler for the CPU does the same thing, this means that I have better temperatures on the air entering the fans. For all components.
Closed loop water cooling as an exhaust lol it should be intake. Also, I lol to having closed loop watercooling when you only own a GTX 1070 and that watercooling won't do crap to help over a better GPU.
If your place your radiator on the intake then sure, you'll have a slightly higher delta T due to the cooler incoming air and your water will go back to the component slightly cooler. However, you're now dumping all that heat you removed right back into the case surrounding the component you just cooled. Doesn't make much sense does it? Remove heat from the CPU and dump it right back around the CPU which makes the ambient temperature skyrocket. You don't remove any heat from the case in that scenario. Then you have to add additional fans to get even higher airflow in the case to reduce ambient temperature.
Now if you place the radiator as an exhaust all the heat from your CPU is going to be exhausted directly out of the case. In a radiator exhaust setup your ambient temps are also going to be much lower and this means the difference between room temperature air outside the case and ambient temperature inside the case won't be that different.
The added bonus for exhaust radiators? You need less fans in the case for airflow which reduces noise as well. The radiator exhaust setup is just more efficient unless you plan on having a wind tunnel in your case and want to spend more money on fans.
Most people who experience overheating issues typically don't overheat the CPU itself, more often it's ambient temperature related because they're dumping CPU and/or GPU heat right back into their case increasing all the temps across the board.
Also, while it's been ignored by many posters, the non-reference GPU cooler is a horrible setup for SLI because your top card is dumping all the heat onto the bottom card, not to mention there isn't great airflow for multiple fan exhausts anyway. There is a reason the back exhaust cooler is the reference design...it's made to work in SLI mode.