That is the infamous "LaMancha", a Plymouth that was to be produced in limited numbers for discriminating customers in 1969. Unfortunatly, a fire on the production line shut down any chance of this forum being called 69LaMancha.net.
Seriously... It was a Plymouth concept car called either the Duster I or the BeepBeep X1. I've heard it called by both names, with the Duster name most often.
The other... well.. its a two piece replacement floor pan. Nice looking car though.