PC Build

[gt1551]

So to start off very briefly I am going to be building a custom pc with the following as parts:

First here is the build:

CPU: Intel i7-7700k

GPU: Asus Strix GTX 1080 ti OC

CPU cooler: NZXT Kraken x52

Case: Corsair Crystal 460x RGB

HDD: Seagate Barracude 2tb

SSD: 1TB Samsung 850evo

Motherboard; Asus MAXIMUS IX FORMULA

PSU: Corsair HX750i 

RAM: Corsair 16GB DDR4 Vengeance 3200MHz

Extra case fans: 3xRGB SP120 Corsair + 2 AF120 Corsair 

 

I have a few questions to ask, but before I do, I am going to attach a sketch (it is an appalling work of art)  of how I was thinking of putting all this together. Yes it does look like an aardvark, when it comes to art, but I've tried to illustrate my build plan well, and marked the directions of airflow in green marker to highlight them.

 

1) Am i going overkill with the fans? And is there even space for them?

2) a) Im curious to if the gtx 1080ti that I have chosen is good and performs well amongst all the other choices there are out there

    b) Im hoping to one day purchase a second gtx 1080 ti and run sli on my pc. The current card I have chosen takes up 2.5 slots to my understanding, however I have no clue if my motherboard will support 2 x 2.5 slots. Could you help me out?

    c) If I do plan on going into SLI, would I need a better PSU (like a 1000W?)

If it does not, could you recommend 2 cards of similar performance with overclockable headroom that could run sli on my current motherboard

3) Im hesitating between the case i've currently put up, the Corsair 570X, or the Phanteks Enthoo Evolv Glass case. Are there any advantages or disadvantages between these 3 and what would you personally recommend?

4) Any other pieces of advice you can give me? Im 100% set on the processor as it is. Everything else, I am happy to receive your potential replacement recommendations for, as well as a reason for your recommendation.