Is this PC good for Unreal Engine 4? Are there any changes I should make to the PC to make it better without effecting the price that much?

Do you have any sights to buy a Windows key? Like eBay? And should the EVGA Superclocked edition for the 1070 be good? I dropped my memory down the the DDR4-2666 (Crucial - Ballistix Sport LT 16GB (2 x 8GB) DDR4-2666 Memory) because I heard that you shouldn’t go anywhere below that for productivity.