Is this GPU and SSD compatible with my Aurora R6?

   I have a pair of compatibility questions and I am hoping that someone here might be able to help answer them.

   I currently own an Alienware Aurora R6 desktop PC.  I am wanting to add a Samsung 860 EVO SATA III internal ssd, as I currently do not have an ssd installed at all.  For reasons I won't go into, I would also like to replace my current gpu (an NVIDIA GTX 1060 6GB) with a Sapphire Radeon RX580 Nitro+ 8GB gpu.  I have been reluctant to purchase anything until I was certain that these components were compatible with my system.  Though my model of desktop did originally offer an AMD RX580 8GB gpu option, I am still concerned about the outright hardware compatibility (I have heard references to the amount of pins needed to connect the gpu) and the dimensions of the card.  I have yet to open my case, so I couldn't determine the dimensions of my current gpu via the manufacturer model. I spent a good amount of time looking around the web to determine the space my case has allotted for a gpu, but couldn't find anything. I am curious if anyone else has replaced the gpu in their Aurora R6.

   As for my ssd, I had read that some users found the Samsung 850 EVO SATA III and M.2 ssd's were indeed compatible with their Aurora R6 system.  Since then, Samsung has upgraded their current line of ssd's to the 860 model.  I'm now, once again, left wondering if I'm going to encounter any sort of compatibility issues post installation.

   Thanks for reading XD

  Current System (Stock):

i5-7400

NVIDIA GTX 1060 6GB

16GB 2400Mhz RAM

850W NON-Liquid PSU