i7 3820 to i7 6900k good choice?

hello guys. ive posted a couple of months back regarding building a new pc for $2000 ( quite close to 100k in Philippine peso) that ive saved up for 3 years. now i was getting insights and advice from people her to get the most out of my money. and id be finally building my pc next month. and id be planning to get a complete overhaul again in the next 3 years. same as my i7 3820 system.

now my bugget currently is sitting at $2,300 USD exactly. (converted ofcourse and rounded down, just for reference ill be using USD.)

things to point out.

reason why im going for an x99 rather than the Z170 is that i was able to get an Asus X99 - E WS board that is used for over a year for free. a friend of mine who works abroad got handed used Workstation parts so i was able to get one. and it was installed in his personal PC there so it still works well according to him.

so here are my questions.

is the i7 6900k a good choice? my friend there in saudi arabia said that it costs roughly 1,200 in USD (converted from riyals to USD). and i was hoping to grab one but heres a catch
. along with the free x99 WS board. he got handed a xeon e5- 2699 V3 and a xeon e5 - 2697 V3. he is willing to give either of these CPUs for 1,500 in USD. and 1k USD respectively and he wants it sold fast. so would that be a great deal? or should i just stick for i7 6900K for gaming.


also ill be using my R9 390x which is a hand me down, i dont see the GTX 1080/1070 worth it for now and im willing to wait for the GTX 1080Ti if i could afford it by then.


Prats that im opting for that would go along with my possible build would be these. as they are both available here in my country and saudi arabia/britian. ( i pay my friends to buy parts that arent available here in my country)
these ill be using PC part picker for easier browsing to anyone thats willing to help me out ^_^.

PCPartPicker part list / Price breakdown by merchant

CPU Cooler: Cooler Master MasterAir Maker 8 66.0 CFM CPU Cooler ($118.99 @ Amazon)
Memory: G.Skill TridentZ Series 32GB (4 x 8GB) DDR4-3200 Memory ($154.99 @ Newegg)
Storage: Samsung 850 Pro Series 512GB 2.5" Solid State Drive ($209.99 @ NCIX US)
Case: Cooler Master MasterCase Pro 5 ATX Mid Tower Case ($119.99 @ SuperBiiz)
Operating System: Microsoft Windows 10 Pro OEM 64-bit ($129.95 @ B&H)
Total: $733.91
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2016-06-27 13:01 EDT-0400

are these parts good enough to complement my build?

sure parts would be.

CPU: i7 6900k/Xeon E5's

Mobo: Asus x99-E WS

GPU: MSI R9 390x 8GB/

PSU: EVGA SuperNova P2 850Watt

thank you in advance ^_^