Thank you. I'm not sure if the later Darts are any different, but on the '66, if you have the perimeter of the headliner glued in place with contact cement, it's pretty easy to go around anywhere that's wrinkled, warm it up a tad, pop it off the cement, pull it a little tighter, and re-stick it. If that doesn't work, I've heard several hot/cold cycles may eliminate some of the wrinkles as well. At the end of the day, if there are some wrinkles, it's not the end of the world. Good luck!