Id get a 4690K... no dual cores for a gaming machine these days... no way.
I like that, but he already has 8GB 1600Mhz in dual channel. No point in buying faster since he isn't using the iGPU with his 970.
Well with an over clock it would be fine. I'd honestly just leave the A8 myself its not going to be a major limiting factor as a CPU. I'd just go power supply, GTX 980