2 - 4 horas
I needed to put an SSD as my system disk but I didn't wanted to pay the AppleStore prices.
My first dismantling was a time capsule to change the HDD. This dismantling was only my second experience. Everything went quite well even some of the screws were different, but I used also the 2012 teardown guide.
2 problems :
Impossible to put back the silver metal AC socket retainer. I had to open once again the mini because the piece was moving inside. I get rid of it. Not a big deal.
Once you have dismantle the original HDD it's difficult to put it back exactly in the grommets hole, so I finally put the side screws away (only 2 screws on the HDD to put away).
Very happy with my dual hard drive kit that I got by regular postal service without any taxes (I'm in Paris).
Thanks again !