What should I sell my desktop for, and where?

[cow57xd]

I bought an Alienware Aurora R7 in February 2018. I kind of want to get an almost maxed out Alienware 15 or 13.
Right now I have:
Alienware Aurora R7
Intel Core i7-8700k (amazing, hits 4 GHz while editing a Word doc, only 6% utilization
NVIDIA GEFORCE GTX 1070 Ti with 8GB of GDDDR5X (not sure about the VRAM actually)
Water Cooled 8__ watt PSU
2TB HDD (should I include this or keep?
128GB NVMe SSD
32GB RAM
Windows 10 Pro
A few months left of warranty

I want to buy the Alienware 15, not m15, for its power and good screen size, my MacBook Air is only 13”
I want to buy Alienware 13 for the OLED and touch screen, but it’s definitely not as powerful, and it has less room to expand

What should I sell my Aurora for? Should I sell it? What laptop should I buy?

 

[ScrewySqrl]

Moved from Systems to Classifieds.