Building High-Performance PC? (GTAV, Linux Dual Boot, Compsci, KSP, casual stuff, MC)

So, I'm still feeling this out, but I'd appreciate if I could get some questions answered. (note: Prices are CAD, mostly sourced from Memex, but I'll figure out where to get it)

+i7-6800K/i7-6850K:
The higher end model offers 40 PCI lanes, but is there really an appreciable difference for this? Even running SLI GFX? The difference is $200, so it's worth knowing.

+ Quad channel ram?
Is this worth vs. dual channel, provided of course that the chipset/proc supports 4xChannel?

+ Cooling?
What sort of cooling solution would be required for such a build? I'm not comfortable constructing water cooling....

+ Price?

How much is a person generally looking at for a high performance system? (Ultra, 60fps min, potentially up to 4K) I'm prepared to set aside $3-4K for the following:
- System (I have the OS, DVD, and a 1TB SSD accounted for already)
- 2x Monitors, 1 4K Gsync, 144hz (or potentially just 2K... I'm on 1080, so either is a step up); the other can be 0.5x resolution of the main monitor, no specific requirements. That's purely for real-estate.
- Mech KB/Headset/Mouse

I can forgo the peripherals if needed, but I'm kind of looking for a full refresh. I'd be selling my old desktop (see specs) for whatever I can get for it. I'm thinking I'd try $500-$600.

+ Cases?

I'm looking for a smaller computer case. Ideally MATX (though if this is a bad idea, please enlighten me). Any recommendations? Currently I have an Antec 302, I'd like to get something smaller. Orange is a ++.

Thank you for any of these questions you may answer!

I'm planning to build this around Christmas to take advantage of those sales.
 
Solution
Orange/Black theme in a full tower chassis, the case has a tempered glass panel but is currently out of stock @ Newegg.ca.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-6800K 3.4GHz 6-Core Processor ($519.99 @ NCIX)
CPU Cooler: Noctua NH-D15 82.5 CFM CPU Cooler ($108.99 @ Amazon Canada)
Motherboard: Gigabyte GA-X99-UD4P EATX LGA2011-3 Motherboard ($326.47 @ Amazon Canada)
Memory: G.Skill Ripjaws 4 series 32GB (4 x 8GB) DDR4-2800 Memory ($230.53 @ DirectCanada)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($89.75 @ Vuugo)
Video Card: EVGA GeForce GTX 1080 8GB Superclocked Gaming ACX...
The 6800k is far better value.
Quad Channel RAM is a must have with x99.
A beefy air cooler is the best choice for quiet, consistent and cool long term operation.
You want at least ATX with x99 for airflow, cooler height clearance, and better mobo support.
1440p 144hz G-Sync and a 4k monitor seems like your best option.
I'll make a list.
 
Orange/Black theme in a full tower chassis, the case has a tempered glass panel but is currently out of stock @ Newegg.ca.

PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-6800K 3.4GHz 6-Core Processor ($519.99 @ NCIX)
CPU Cooler: Noctua NH-D15 82.5 CFM CPU Cooler ($108.99 @ Amazon Canada)
Motherboard: Gigabyte GA-X99-UD4P EATX LGA2011-3 Motherboard ($326.47 @ Amazon Canada)
Memory: G.Skill Ripjaws 4 series 32GB (4 x 8GB) DDR4-2800 Memory ($230.53 @ DirectCanada)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($89.75 @ Vuugo)
Video Card: EVGA GeForce GTX 1080 8GB Superclocked Gaming ACX 3.0 Video Card ($839.98 @ DirectCanada)
Case: be quiet! DARK BASE PRO 900 | ORANGE ATX Full Tower Case ($319.99)
Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($119.99 @ Newegg Canada)
Monitor: Acer XG270HU 27.0" 2560x1440 144Hz Monitor ($544.99 @ PC Canada)
Monitor: LG 27UD58-B 27.0" 3840x2160 60Hz Monitor ($449.99 @ Newegg Canada)
Keyboard: Corsair K70 RAPIDFIRE Wired Gaming Keyboard ($134.98 @ DirectCanada)
Mouse: Razer DeathAdder Elite Wired Optical Mouse ($79.99 @ NCIX)
Headphones: Kingston HyperX Cloud Revolver Headset ($109.25 @ DirectCanada)
Total: $3874.89
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-12-02 22:08 EST-0500
 
Solution
Here's a smaller, more cost effective variant that I recommend over the above build.
PCPartPicker part list / Price breakdown by merchant

CPU: Intel Core i7-6800K 3.4GHz 6-Core Processor ($519.99 @ NCIX)
CPU Cooler: Noctua NH-D15 82.5 CFM CPU Cooler ($108.99 @ Amazon Canada)
Motherboard: Gigabyte GA-X99P-SLI ATX LGA2011-3 Motherboard ($299.99 @ Memory Express)
Memory: G.Skill Ripjaws 4 series 32GB (4 x 8GB) DDR4-2800 Memory ($230.53 @ DirectCanada)
Storage: Seagate Barracuda 2TB 3.5" 7200RPM Internal Hard Drive ($89.75 @ Vuugo)
Video Card: EVGA GeForce GTX 1080 8GB Superclocked Gaming ACX 3.0 Video Card ($839.98 @ DirectCanada)
Case: be quiet! SILENT BASE 600 w/Window (Orange) ATX Mid Tower Case ($123.48 @ DirectCanada)
Power Supply: EVGA SuperNOVA G2 650W 80+ Gold Certified Fully-Modular ATX Power Supply ($119.99 @ Newegg Canada)
Monitor: Acer XG270HU 27.0" 2560x1440 144Hz Monitor ($544.99 @ PC Canada)
Monitor: LG 27UD58-B 27.0" 3840x2160 60Hz Monitor ($449.99 @ Newegg Canada)
Keyboard: Corsair K70 RAPIDFIRE Wired Gaming Keyboard ($134.98 @ DirectCanada)
Mouse: Razer DeathAdder Elite Wired Optical Mouse ($79.99 @ NCIX)
Headphones: Kingston HyperX Cloud Revolver Headset ($109.25 @ DirectCanada)
Total: $3651.90
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-12-02 22:10 EST-0500
 


Wouldn't affect anything, bu I recommend getting a decent external USB 3.0 Hub though.
 


Just double-checking since you mention a hub in the same post, do you mean it wouldn't affect if I used a hub, or it wouldn't affect if I used a PCI USB card? I intend to have a hub, but it seems kind of dumb to buy one and use 5/6 slots for permanent dongles. I was thinking I'd get the card and then just buy a cheapo hub on ebay since it's rare I need beyond my PC capacity (or at least, with this plan) for peripherals and whatnot.
 
Not really overkill, a single 1080 will power a 1440p 144Hz display just fine.
If you want G-Sync with that you're dropping another $300, THAT would be overkill.
OP needs those specs for rendering etc. read the original post, it's not a gaming system exclusively.