My new $420 refurbished 2015 Mac Mini has security torx, so i couldn't replace the lazy HDD by an Intel 520 SSD... until i fixit !!
What is strange is that my friend Mac Mini, exactly the same, has no security torx but standard
not so difficult, i think less time than 2012 mac mini.
Very easy to upgrade to Full 2,5" SSD a 2015 Mac Mini, that become enough speedy for regular productivity work.
T6 Torx Screwdriver
Magnetizer / Demagnetizer
Mac mini Logic Board Removal Tool