[lkchris]

You have to remove the carpet covered vertical trim. There's a Phillips screw buried in the carpet. There are also Allen head screws holding this trim-- just loosen, do not remove them. The lugs on the trim are slotted and slip over those screws.
http://www.renntech.org/forums/tutorials/article/110-preparing-a-boxster-for-a-hardtop/