I’ve been reading about the issues many of us face with these aftermarket headliners. I saw a couple of people recommending double-sided tape, Velcro, and even drilling holes. But, if you’re looking for a fix that’s a solid 95% improvement, just screw in your visors! I have mine pretty tight, but when not in use, and even in use, it seems to hold up the “dip” right above the rearview mirror perfectly. It has a little bit of play, maybe half an inch, but it’s a nice workaround. This might’ve already been posted, and I’m sorry if it has, but it’s been on my mind for the last couple of weeks.

Hope it helps somebody!
-1989Jack

Mirror’s down so I’m not in the picture!