Should I install firmware for Samsung SSD 850 EVO? I've a Mac Mini Late 2012 model that I've recently replaced the HDD to Samsung SSD 850 EVO. Everything works fine(except damaged IR Sensor) and my Mac startup speed is fast. I've been searching around Google about the Firmware particularly for 850 EVO but there's no firmware to download from the firmware download page , and seems like there are problems regarding the firmware download for 850 EVO PRO model. 

Since the firmware is not found, is there a need to download and install the firmware? And since Samsung Magician is not supporting Mac OS, should I download a 3rd party TRIM enabler(like DiskSensei) or enable the TRIM support manually? Is TRIM necessary for every SSD?
As far as I can see there currently exists no firmware upgrade for the 850 PRO.

As for TRIM, it is generally recommended to enable it (OS X does on its stock SSDs). There is now a new tool in OS X that will allow you to easily enable TRIM on non-Apple SSDs:

sudo trimforce enable