Mustangace

Pairing an i3 8350K with an RTX 2080 is like going to a job interview wearing sneakers and a suit.  Will not impress your prospective boss.  
Ok, some people actually do that, but it's usually unwise. 
 
Of course, I suppose you could upgrade your CPU at a later point should you find out that it is actually holding you back.  Personally, I tend to be proactive, going with what I think would be a good fit of both CPU and GPU.
 
Yes, don't skimp.  The i3 8350K has 4 cores, no threads and the i5 8600K has 6 cores, no threads.

Pairing an i3 8350K with an RTX 2080 is like going to a job interview wearing sneakers and a suit.  Will not impress your prospective boss.  
Ok, some people actually do that, but it's usually unwise. 
 
Of course, I suppose you could upgrade your CPU at a later point should you find out that it is actually holding you back.  Personally, I tend to be proactive, going with what I think would be a good fit of both CPU and GPU.
 
Yes, don't skimp.  The i3 8350K has 4 cores, no threads and the i5 8600K has 6 cores, no threads.

No more than 1-4 for the wifi (the card he chose is 1x) but that's beside the point. If he does SLI GPUs (one at 16x and one at 8x, since he cant do both at 16x no matter what with the 6800k), and wifi then that's already 25/28 lanes. If he wants to add an M.2 or PCIe SSD later, that takes 4x which means he drops the 16x card to 8x. He sounds he's saying the price is not really an object so I'd tell him to do the 6850k, but definitely not the 6900k for gaming. I just meant that your recommendation of the 6800k may not be the best choice for him if he can afford the extra $200 for the 6850k.

you're just jelly because you went with the 6600k instead of the 6700k and went overkill on the PSU

In the UK, there's a problem with that.
 
Both CPUs are basically the same price, so you'd be looking at motherboards more than anything, and they can be pricey on the X99 platform.
Really, the motherboard is the only factor that is going to affect how much you dish out for your system. Though, I do still intend to acquire the X99 platform since it calls out to me. Do I need it? Heck no. Do I WANT it? Absolutely!

Upgrade your CPU then later on upgrade your GPU

Personally, that's what I would do - upgrade the cpu first.  
 
I was forced, due to HD failure in my i7 system, to use my backup computer with an old AMD Athlon 64 X2 4800+ dual core cpu to play my favorite game with my GPU from my i7 system, thinking it would work just fine because it was the same video card.  No. No, it did not work just fine - the cpu became a bottleneck, making the game almost unplayable even on lowest settings.  Now, having said that, I'm sure an Intel i3 Skylake processor is a much better dual core than that old 2005 model AMD Athlon 64 X2.  But because of my experience, I just have to go with upgrading the cpu first. 

The only thing i would change to your build is to add an ssd , they make a world of a difference in almost every task. It will speed up every task that isn't gaming 

Why not go for the more recent Skylake build? They cost about the same and you benefit more from it. To answer your question, you should be fine for the most part. Audio editing is a cake walk unless you are planning on recording real instruments and have accuracy monitoring the sound(not needed for production). Streaming is fine but it is CPU intensive so you should probably get the more recent architecture to be on the safe side(6700k). 

OP, I have a 380. good enough card. I would keep it a couple more years. I'd invest in a multi core multi thread cpu ( 4/8 ) (6/12 ).

This might be better addressed in the NVidia GeForce forums or support section there.  https://forums.geforce.com/