Welcome to the site, Triple 7.
Charlie's indication of the merits of being able to see something that is used before buying it are very true. T-5s are said to be a 100,000 mile transmission. That refers to 'normal' usage before rebuild is necessary. -Perhaps a better wear indicator would be to KNOW the driving habits of the previous owner.
Miker's link to the article from ModernDriveline that gives the development history of the T-5 is well worth your time to read and reflect upon. All T-5s are NOT the same. Swapping transmissions is not something you want to do twice.
My shop teacher used to say, 'Why is it there is never enough time to do it right, but always enough time to do it over?' And then there's the money angle of doing something a second time.
NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York