Warning: lengthy post, sorry in advance. Long time lurker and enjoyer of what is posted. 

Last year or so I bought a Lenovo from a guy that had upgraded. Said he used it for gaming and such, and honestly it does okay for what I do. 

I am wanting to upgrade the graphics card at the minimum. As I started to type this I realize I don’t have what the stock PSU is, but I assume it’s low. 

With that, I have 3 questions. 1) how high can I upgrade the GPU on this motherboard? I’m not looking anything crazy like 4-5k, was thinking 1060 minimum, but have seen some 1660 and even a 2060 decently priced on fb marketplace. 

2) would I need to upgrade the PSU depending on what GPU I get? And is there such a thing as “too much”? (Getting a 900 or something if I find a deal on fb, just to save on future upgrades)

3) am I just better off looking at a “complete upgrade/overhaul” of motherboard and such? I found one on FB marketplace (noticing a trend of where I look to buy? lol) that’s from a prebuild, guy says it’s a Asus z170-k with an i7-6700k chip. Looking online as best as I can/know, it seems like a decent board that I can add some decent upgrades to. Anybody have experience with them and how “outdated” is it?

Thank you in advance, even though I will be saying it in reply anyways. 

PC upgrade question