I have £1000 +/- 10% that I would like to spend on preferably a mining rig with GPUs (although i'm not put off by ASICs). My initial plan would be to mine etheruem (although I am aware it is going to be fully POS soon). I am new to this so would appreciate any suggestions. I have put together a basic rig (https://uk.pcpartpicker.com/list/W6rwGf). All I would need is a CPU/mobo combo.

Also, would I need a mobo that supports 4-way crossfire or just one with 4 PCIe slots?

If I'm being dense please tell me!