Yes Keri, I have done them all myself. But perhaps not the way the pro,s install them, making mods to suit my own needs. The hardest part is running the ducts if the basement is all finished. If not then its not to bad.
http://nutech-energy.com/life.htm
I ran my return fresh air different than specs say, depending on the amount the places were finished. My home in Thompson had a nice crawl space, so it was fairly easy.