Maybe. If you could finally tell me which settings you're going for in games I could tell you if it's worth reusing the GPU.

Yes. To make it even clearer: Overclocking Intel CPUs does not improve price/performance, only performance. For AMD CPUs it's free anyway and you can decide later. SLI/XFire do not improve price/performance or performance most of the time because most games don't support them (or only nominally support them). Watercooling doesn't improve price/performance or performance either. Zen hits a wall way before cooling cooling becomes a problem if you're not going for "I'm going to run this benchmark 3 times then the CPU dies"-voltages and Intel CPUs should be delidded when cooling is a problem, which is far more effective and cheaper than watercooling.
So I will ask again: Do you want (or "need") any of those?
Depending on the settings overclocking won't help because you'd be limited by the GPU (except in TF2) and more cores would be cheaper for streaming.

The 4670 uses DDR3, any new CPU uses DDR4. It doesn't matter which sticks they are, if you've got an i5-4670 I can guarantee that they will not work with a new CPU.

For BF1 on 1080p it would be a downgrade.
https://us.hardware.info/reviews/8113/6/crossfire-a-sli-anno-2018-is-it-still-worth-it-benchmarks-battlefield-1-dx12

If you want a new CPU, not used, you won't be able to reuse the RAM.

Also swapping an 80-90W CPU for a more powerful 80-90W (or more) CPU will not help you with the heat. If you can't cool the 4670 properly then either the airflow is pretty bad (wouldn't be surprising with mini-ITX) or the cooler is shit (spoiler: it kinda is) or both.

You still didn't answer the questions about settings and overclocking/watercooling.

What circumstances?
Why SLI?
What do you mean with "overclocking/sli/watercooling is ok"? Do you want them or not? They all cost money.
What are "high end games"? What settings and resolution are you going to use?

You need DVI-D dual link for 4K or 120 Hz. VGA will never run as DVI-D dual link because it is neither digital nor DVI.

If you didn't change the cable either your adapter or your settings are fucked. Or at least it's not plugged in properly.

1. You need a DVI to VGA adapter, the signal is coming from the DVI port on the GPU, not the other way around.
2. DVI-I is DVI-A (analog) + DVI-D (digital). VGA is analog.
3. DVI dual link is strictly digital. VGA is analog. Taking the digital DVI signal of a DVI-I port and converting it to analog VGA would be absolutely retarded. DVI-I/A to VGA adapters literally just exist to change the plug type, the signal is identical. Therefore DVI-I to VGA and DVI-A to VGA adapters are exactly the same and will never support dual link.
4. Why would you need dual link for a 60 Hz monitor?
5. Your brightness setting is wrong.

Any reason why you're upgrading? You won't need an 8700K for either btw.
No, PUBG is just a piece of shit.

1060 needs 120W, oc'd ~150W, about the same for the 8700K, so even with plenty to spare you won't need 650W. 400-500W is fine. 80+ is an efficiency rating. The best well automatically reach Gold or better because there's no pointing in making a good platform less efficient, but even mediocre designs can reach Gold so it doesn't tell you much about quality.

How are these for what? It all depends on what you're going to use them for.
Not sure you need a 650W PSU either.

Yes, if you can wait, wait.

Yes, if they send you one (might be Aer P instead, don't think they've got any FX V2 left) that's always going to be cheaper.
If you're not running the FX V2 at full speed you could get away with an NF-P14s redux-1500
http://www.coolingtechnique.com/recensioni/air-cooling/ventole/1490-recensione-noctua-redux-e-industrialppc.html?start=10
http://www.coolingtechnique.com/img/rece/ventole-rheobus/noctua/redux_ippc/pressure-redux-internal.png
and even if you do there are cheaper options.
http://www.coolingtechnique.com/recensioni/air-cooling/ventole/1659-recensione-bitfenix-spectre-pro-120-e-140-pwm.html?start=1
http://www.coolingtechnique.com/img/rece/ventole-rheobus/bitfenix/spectre_pro_pwm/pressure_140mm.png
https://skinflint.co.uk/bitfenix-spectre-pro-pwm-white-bff-spro-p14025ww-rp-a818023.html?hloc=uk

No, with 2000 and 1000 rpm fans the noise from the 2k fans will dominate anyway. As long as they can push enough air through a dust filter it's fine.

3dB is not double the volume.
3dB would be twice the power, since power is a power quantity (duh) or sqrt(2) the sound pressure, since pressure is a root power quantity (you can guess where that name comes from).
10dB or 10 times the power or a bit over 3 times the sound pressure is percieved as being twice as loud.

For reference: https://www.audiocheck.net/blindtests_level.php?lvl=3

Yes, against the FX v2 it might be slightly in favour of the NF-A14 iPPC-2000 or not, but the FX isn't an option because that's the broken one you're trying to replace and against the ML140 PRO it's no contest because that thing sucks. I mean if you look at free flow CFM it's 106 for the NZXT, 103 for the Noctua and 90 for the Corsair, but the NZXT is the loudest and the Corsair is the quietest. Similar for static pressure at no flow. NZXT and Corsair almost equal, Noctua a bit ahead.
But now look at what happens at 1mmH2O. NZXT and Noctua get something between 85 and 90 CFM, but the Corsair drops below 60. And it only gets worse the higher you go.

Italian is indeed not English, very observant.

Sorry, I skipped straight to the GP14.
I don't have anything for the V2 but it shouldn't be too different.
http://www.coolingtechnique.com/recensioni/altro/aio-liquidi-compatti/1280-recensione-nzxt-kraken-x40.html?start=4
So the difference would be more like 3dB total.

Also we're talking about rads so there will be significant resistance and in those cases you should probably have a look at these.
http://www.coolingtechnique.com/img/rece/AIO/NZXT/kraken_X40/pressure.png
http://www.coolingtechnique.com/img/rece/ventole-rheobus/noctua/redux_ippc/140-esterna-pressure.png
http://www.coolingtechnique.com/img/rece/ventole-rheobus/corsair/ml/pressure_140.png

Because on paper the ML140 PRO looks decent, slightly lower static pressure and CFM than the NF-A14 or the FX-140KRX but in reality it sucks dick.

http://www.coolingtechnique.com/img/rece/ventole-rheobus/corsair/ml/corsair_ml_140_data.png

http://www.coolingtechnique.com/recensioni/air-cooling/ventole/1731-recensione-ventole-corsair-ml-magnetic-levitation-fan.html?start=6

http://www.coolingtechnique.com/img/rece/ventole-rheobus/noctua/redux_ippc/a14_ippc_data.png

http://www.coolingtechnique.com/recensioni/air-cooling/ventole/1490-recensione-noctua-redux-e-industrialppc.html?start=9

http://www.coolingtechnique.com/img/rece/ventole-rheobus/noctua/a-series/a14-flx-data.png

http://www.coolingtechnique.com/recensioni/air-cooling/ventole/1153-recensione-ventole-noctua-a-series.html?start=7

NF-A14 PWM or FLX shouldn't be 5£ more expensive than the ML140 PRO though.
NF-A14 industrialPPC-2000 (PWM or not, but PWM is the only one that would cost 5£ more) or ML140 PRO are both the wrong choice.
If you're bothered by clicking on a 1000 rpm fan you're probably not going to appreciate the noise a 2000 rpm makes when operating normally.

Then he didn't even try to find an answer and I am very disappointed.
I mean surely on a website called "teamfortress.tv" someone must've built a PC for TF2 before.

Yeah but he's got to be in the hardware subforum to even post this so to not even notice the stickied big fat "PC Build Thread" right below "Start Thread" requires a worrying level of tunnel vision.

Is there some special reason why this couldn't be posted in the PC Build Thread?

You could've read a bit and answered the questions already that I now have to ask.

When are you going to build it?
Do you need a monitor/peripherals?
Overclocking yes/no?