2 - 4 horas
Had a nice display (matte!), but needed faster Mac. MacPro's are overkill, too much $. Basic Mini, souped up, was best choice for my needs (I'm a photographer, often with a thousand photos to sort through and fix up).
It's a worst case situation - everything must first be removed, which is scary. Instructions very good except an important detail of reinstalling HD goes unmentioned - getting the two bumps into the corresponding holes is important and tricky. Some greater detail on the technique of unplugging wires would have been welcome. The included tools did not include a T8, did not match the picture on the website at the time I ordered.
Putting the HD back in requires fiddling. The four rubber grommets for the second drive are now identical, but getting them in is not difficult.