Alienware 17 r4 6700hq motherboard re-sale?

Hello, I was planning to test out whether or not I could put an upgraded motherboard into my current system. That however leaves me with a i7-6700hq GTX 1070, fully functioning motherboard.
I know that people sell their pulled parts on ebay and other websites but I was wondering what is the likely price that I could actually sell it at, and is it likely to sell at all or am I gonna have to put it in a parts bin?

 

Ebay sellers are usually pretty good about posting up pictures. Compare the boards very very closely. If there's any discrepancy in screw holes, cable/connector locations and sizes, I would say don't do it. If everything lines up. Go for it. There are some things that are going to be different, like the location and arrangement/number of capacitors and VRMs ... those are minor, so long as they make contact with the heat sink, it's okay. Which, don't forget to check for those kinds of things especially. VRM and Memory Module heat sink contact is very important.That's probably the biggest one. Upgraded Motherboard may mean upgraded heat sink too.

If you get it, and it still doesn't work. Fess up, and return it. Maybe only buy from an e-bay seller with a return policy.

 

The board I plan on using is the i9 with GTX 1080 from the 17 R5. The boards are exactly identical except for a single mounting screw for the CPU heatsink which if I get the i9 heatsink wont be an issue. VRMs and Memory modules is definitely a concern of mine however I've found some forums on the proper pad thicknesses to use and where to put them so that shouldn't be an issue either.
What I mainly mean to ask is if I will be able to market my old motherboard for some sort of cash? Cause considering the price of the new board ~$1200 and the price of my board on ebay ~$600 the upgrade should only cost me about $600 but if I can't manage to sell the old board then I might as well try to sell my laptop entirely and just buy the i9 model off amazon for $2100.

(edit) another concern is whether or not my hardware will plug right into the new board. I.E my power plug, Keyboard and mouse connections, etc.

Also I have a resource for finding Genuine Dell parts that are either pulls or surplus parts from Dell themselves. ill only use ebay parts if i absolutely have to.
https://www.parts-people.com/