Thanks for the reply, When I look at the back of the case there is a spot for a wider GPU card, I'm having trouble finding out the exact model of gtx780 that's used in the higher spec model and how to buy the double brick power supply as I only have the single one.
I am aware I will void the warranty this doesn't matter to me, I just need to find the info I need to do this myself .
I've been out of the desktop game for a while, there are so many GTX780 variants around 😮