Aurora R13, maximum HDD size 2TB?

That is the largest HDD Dell tested in the system but is not the largest that will work properly. You can easily go to a 4TB SSD or larger with an HDD.

When I upgraded from an R9 to an R13, I moved the 4TB drive that I had over without any issue.  I would imagine that there is no limit, but that they simply did not test it.

correct they have not tested any size greater but the fact is a dual sided m.2 won’t fit hit is to large and hits the stand-off for the smaller size card.  4TB is dual sided so it more than likely not fit. 

.. So its clear that the ammount of storage is not a issue for whatever Aurora, and agree, there is no limit. And as far as i know dell didnt test it because its not a issue. you wanna install a ten thousand TB into your R 13 or R  9, please do so if it was available

That table simply indicates what sizes they validated. That does not mean larger sizes do not work. They will work as long as you format them in the GPT format.