I wanted to install a SSD to use as a boot drive to boost performance but also keep the stock 500gb drive to store my media.
overall it went quite well but the instructions were not entirely correct
If you are installing a new drive to be the boot drive make sure that you install that drive using the cable that is already in the mac mini. The instructions say that this is not necessary but in my experience it definitely is. I could not get my boot drive/starup disk to boot if it was installed with the drive cable that came with the kit. I switched the 2 and both drives are working great.