I needed a larger HD.
So-so. Some steps were not described: removal of fan and shroud screw fasteners (Torix #6), and separation of the adhesive tape holding the plastic film onto the existing drive prior to removal of its major connector.
Worst was failure to boot after installation. All attempts produced an exclamation mark image above "apple.com/support" text. Suspecting faulty installation I took the Mini to Apple and discovered the drive needed to be formatted--an option not available until a Genius did genius stuff. After that, all went well.
Search the web for other videos-that worked for me.