You can't overclock on a B-series Intel motherboard. You should get a Z-series if you want to overclock. Also, with a Z-series you can get faster RAM like 3000 or 3200.
You shouldn't get 2 separate kits of RAM. Just get a single, larger kit if you want more RAM. 16GB is plenty for gaming.
Some people would say get a better PSU, but that one is good it's just not the best. I'm liking the matching Thermaltake components.
There's no GPU.