You won't be using all 8 cores of fx8320 anyway.
I have one but I do rendering and stuffs...
The fx6300 is the way to go if you only want to game...there is a reason why its the best processor in its price range with head on competitors from Intel twice or more in its price!!!
Pair it with a 990fx mobo from the few bucks you saved from it rather than cheaping out with some low end 970 mobo. Both chip sets works anyway!!!
Noctua is really a pricey option. Lots of other good quality coolers are available in the market in less price. AMD CPUs come with stock cooler but you are going extreme anyways. I use deepcool frosttwin on my fx8320 mounted on MSI 970a-g46...
I overclocked it till 4.9ghz and the temps were really under control. But I downclocked it to 4.3-4.5 while I do rendering or some gaming. And even I have seen some really hot Intel CPUs .
Go for fx6300, it runs cooler than 8320 and does the same job.