Update 12/16/2016: Minor model changes for even better support of the head. I also found it better to print vertically with a brim and supports, as I had previous issues with the head drooping even with supports on when printing horizontal. YMMV.
Update 08/02/2016: Adjusted length and width of clip. Added more support for the "head" of the clip for improved structural integrity. I strongly recommend removing the adhesive backing from the hook and loop fasteners and super gluing the fasteners to the clips as the adhesive has failed numerously for me especially in the heat. The extensions on the sides of the clip are to allow for more surface area to tape down the clips with duct tape to the metal above the headliner to take off stress on the clip head. Another solution would be to drill small enough holes in your ceiling for zip ties, but I haven't confirmed this as working as duct tape has worked just fine for me, and either way I wont see it once the headliner is on.
Simple clip for the MKIV Toyota Supra headliner. Requires industrial strength dual lock hook and loop fasteners and optionally duct tape. Print slowly at 100% infill.