Swapping a Toilet
 

Three toilets in the house. One on the first floor is the worst, they are all the old fashioned kind (3 or five gallon flush, i forget which, but it's a lot).

My wife would like a new small gallon Flush model upstairs, and she says to take that one and put it on the first floor and dispose of the first floor one.

Thoughts? A lot of work? Less work to just swap out both with new? I have never installed a toilet, how much work involved?

Thanks!