While you're doing the headliner, take the time to PAINT the plastic trim. I chose a gray that matched the leather. Spray paint especally made for plastic is available from auto paint stores. Don't forget to paint the screw heads !! This is THE MOST GRATIFING PROJECT I'VE DONE SO FAR.
This is also the time to fix roof drains or put in a new roof antenna. How about a light bar ??
REMOVING THE HEADLINER
Removing the old headliner is pretty straightforward. Just remove everything (yes, even the interior side plastic panels... I think they're called sail panels?) and the rear-most panel also (you have to remove the rear shoulder belt hold-down bolts; the most aggravating thing of all, I think). The old headliner panel slides out through the hatch. A second person to help makes this entire process most helpful and expedient. If you have a moonroof, just remove the trim thing (u-shaped); it pries right off. The light console screws are easily accessed by opening the sunroof since they are on the top of the car. No need to remove any of the moonroof hardware except for the winding handle. A reversible power screwdriver with a Phillips bit makes quick work of all the removal stuff.
INSTALLING NEW HEADLINER MATERIAL YOURSELF
I wouldn't recommend trying to salvage the old headliner. I tried that; it doesn't work and makes a real mess of everything. Especially since installing a completely new one is fairly cheap and looks incredibly better.
I bought the material at an automotive trim shop. They sell the headliner material by the yard and it comes in a variety of colors. It comes in two thicknesses also; I wound up with the thicker (I think it was 0.25 inch); the thinner (can't remember exactly but it was probably just 0.125 inch) would be better but it wasn't too important. My shop didn't have the thinner material in the color I wanted. I was able to match the old headliner color almost perfectly. I think enough material to replace my old one cost about $20. The glue is much more expensive: $14 a can and it takes just a little over one can. Don't scrimp on the glue and forget the 3M product (been there, done that). I used "Super Bond Trim Adhesive" by SOSMETAL Maintenance Products (for professionals). Sosmetal No. 211417; bought at the trim shop.
Strip off the old headliner material; mine came right off. I then used a stiff wire brush to clean off as much of the old glue as possible from the hardboard liner. The old glue is yellowish-orangeish and yucky. The more you get off the better although getting the old panel absolutely clean isn't imperative. The new headliner material is foam backed and the foam backing will disguise any old balled-up glue that you leave behind. Be sure to clean your hands REALLY well before handling the new material.
Then spray a good, thorough coat of glue on the panel. If I remember correctly, after the glue set up on the panel, I then laid some wax paper over the glue-covered panel and then carefully positioned the headliner material (you'll definitely need some help doing this part). Working from the center of the panel, first spray the material with a coat of glue and, after it sets up (only a few minutes), remove the wax paper a strip at a time and press the material into position on the panel, working from the center toward the sides and the ends, work out any bubbles, etc.
Be advised that once the glued fabric meets the glued panel, it's stuck pretty much forever so caution would be a good thing.
Leave about an inch or two around the entire panel. After you've gotten the material attached to the panel, go back and trim off the excess with a sharp razor. I folded about a half-inch of material around to the back side of the panel to make a trim appearance (this is where the thinner headliner material would be easier to work with. If you have a moonroof, do the same thing here, trimming carefully and wrapping the excess.) After it was all done, I then used a brayer (a little roller thingie used in newspaper composing rooms and art departments) to roll down the material evenly over the entire panel to make sure it was firmly attached.
Most difficult part of the entire operation was reattaching the trim piece around the moonroof opening. I think the whole job took me about 3 hours; the next time, this would be about a 90-minute job.