The stock 5400RPM drive was not fast enough in my Mini so I wanted to replace it with an SSD and use the 5400RPM drive as a second drive for storage in the Mini.
The bottom line is I'm very thrilled with the outcome. iFixit's kit was worth the $$ in my opinion and comes with a tools you can always use again if you need to get into any Apple computer and the logic board removal tool for the Mini if you ever need to easily remove that again. One last thing, after tearing the Mini apart once I have lost all nerves about having to do it again. The instructions provided were clear and detailed. Everything made perfect sense.
Just go slowly, take your time, and be patient.