Unless you can magically fit a one piece floor through the trunk opening, go for it, but if you are like the rest of us, do the two piece. The factory put the trunk floor down first and built around it so you can't put a one piece floor through the trunk opening. I used the two piece floor from year one and was happy with the fit, not perfect, but is any aftermarket body panel?

you can see the pics of my trunk floor replacement.