Okay here we go guys. This mod took about 4 hours to make.
ATTENTION!!! I DO NOT HOLD RESPONSIBLE IF YOU DAMAGE YOUR HARDWARE REPLICATING THIS MOD. YOU ARE DOING IT AT YOUR OWN RISK. ATTENTION!!!! STEP 1: KRAKEN G10 MOD I started by cutting the side of the Kraken G10 to make it fit inside the cage of the G20 GPU slot.
STEP 2: PCI BRACKET MOD In order to fit the tubes through the PCI bracket, I had to cut the mesh to lead the tubes through:


File the edges down to make it smooth and can't damage the tubes and wires:
STEP 3: CAGE MOD Cut the cage so the pump can go through it and via the newly cutted PCI bracket:


STEP 4: ASSEMBLYTime to try to fit the Kraken G10/Corsair H90 Combo inside the cage. A bit tricky but you will eventually get there.
I used the Noctua fan controller (NA-FC1) and a 4-pin PWM to VGA fan adapter to control the fans via PWM. The 3 output fan headers were used for:
- Radiator fan
- Pump
- 92mm fan for VRM cooling
STEP 5: TESTBOOT (IT'S ALIVE!!)I carefully lowered the cage inside the G20 and tightened the screws and went to test if this mod even worked. Held my breath and pushed the power button. IT'S ALIVE!!!
STEP 6: CLEANING UPSince the Noctua fan controller was entirely PWM controlled, I decided it was unnecessary to have it outside the G20, so a littlebit of cablemanagement later, I fitted all of the excess cables inside.

And close the lid
STEP 7: TEMPS AND OVERCLOCKWell all I can say is that this mod took a lot of planning, since I didn't want the AIO to show. But it was all worth it based on what result I got:
Here is the Asus GTX 1080 Turbo at stock, running Heaven benchmark. The card hits the 85C mark and starts to throttle. I kept the fans running in auto.

I did another test with the card overclocked, this time 100% fan speed (this thing is screaming at the point):

Although I reached 1974 MHz core, the clock was unstable and the screen froze from time to time.
AFTER MODThis is the result after 15 minutes of Heaven benchmark running:

The computer is dead silent, and it doesn't even sweat. I managed to push the core to 2050 MHz and the memory to 5300 MHz. I think to push it more a volt mod is needed, but at this point, I'm more than satisfied with the result.
I hope you guys enjoyed this mod/guide and I wish you all a nice day!