I'm about to embark on a similar task.

Lifting the third row seats sure is fun! <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

Made even more fun by the presence of the rear a/c on the passenger side of the cargo area.

I wonder how much it would have costed Mitsu if they just put in a speaker grille that could actually be popped off without resorting to major surgery.