[calev]

Primary concern is performance for Kodi. Not interested in Netflix. All content is on 4TB HDD

Was under the impression the n2+ was the best for performance? 

If I went for the Beelink would it be best to leave as Android box or change it to CoreELEC (is this easy)?

Edit: have just been offered a Minix u22 XJ Max at a similar price to the Beelink
​​​​​
Which to choose?

It is pretty easy to delete the android OS and install coreelec to the emmc. You first boot coreelec from sd card and then run ceemmc (one command) from a ssh session. So you'll need to be able to ssh into the box. 

Flashing the n2+ isn't that much easier is comparison.

imo I would go with the cheaper beelink because it has the same processor and ram. Maybe clocked slightly lower to reduce heat. But if you happen to come across a n2+ with emmc, case, powersupply, remote that came out to be less than 130$ then I would get the n2+ instead just because more people here have one.  

But the Beelink will look a lot nicer in the living room. n2+ is kinda hacky looking with it's huge heat sink hanging out.