Removal:
Take off the escutchon over the sunroof latch (if you have the sunroof) DO NOT take off the sunroof latch...
Take off the sunvisors (Hint: mark them for position so you know which hole goes forward Voice of experience...the brackets aren't rotationally symmetric and it's a real pain to figure it out after the fact...gee, how would he know that???)
Take off the interior light cluster
Take off the coat hooks
Using a T-15 TORX bit, unfasten the rearview mirror from its super-glued base on the windshield (this gives clearance to slide the headliner board forward)
Take off the top shoulder belt pivot bolts. (Hint: the plastic covers hinge opposite of the way you'd think...look closely before you pry them apart) You'll need a T-47 TORX for this one.
Take out the phillips screws that hold the rear interior trim to the door posts.
Pull the trim forward and gently inward. Note the nylon "christmas tree" fasteners on each piece which are still stuck to the door post.
Remove the two window top interior trim pieces...there are little spring clips which hold these at the top, and they pull down and OUT to come loose...one of mine broke the plastic tab, but it's not absolutely necessary since the rear end is held by the rear plastic trim piece anyway. The front edge is held by two clip-in gizmos which will pop out of their mating spots on the molding and stay in the windshield post.
Pull the trim strip (rubber molding) out of the sunroof opening.
The headliner should now drop down...be careful, as it's just urethane foam and is pretty fragile, especially with the sunroof hole in it.
Strip and re-cover it or have it done by an upholstery shop (I paid $40, and materials are supposed to run about $20 if you do it yoursel). Do not cut the sunroof opening yet!!!
Replacement:
With an icepick, poke a hole in the new material for each screw that goes through, and make an 'X' cut for each of the sun visor pivots. Also make a slit or 'X' cut for each of the coat hooks.
If you have a sunroof, pull the glass out and set it aside.
Ease the headliner back into place...take it in low and way forward, and slide it back. It helps to have a helper at this point, as the thing is rather flimsy and hard to both hold and move by yourself. (My 8-year-old apprentice mechanic came in handy at this point!)
Take the icepick and locate the screw holes for the coat hooks, sunvisor brackets, etc. It will help to gently bend the headliner down and look in from the side whilst you're doing this step so you make sure you have it positioned correctly fore/aft and side-to-side. Install the coat hooks and sun visors. Install the light cluster. The headliner is now secured temporarily.
Note: The next steps will take a bit of care to keep from gouging the new headliner as you fit the various interior trim pieces back in place. Don't worry about little impressions in the foam that will recover in a few minutes, but do avoid dragging the sharp edge of a molding piece across the fabric and snagging it. A couple of extra minutes' time will be worth it...
To reinstall the window top moldings, carefully release the clips from the windshield pillars and reinstall them in their grabbers on the inside of the moldings. Reposition each one, press the pillar clips home with your hand, and slide the tabs on the top run of the molding into their spring clips on the top edge of each window opening.
To reinstall the rear trim pieces, remove the "christmas tree" pegs from each door post and reinstall them in their grabbers on the moldings. Position the molding so the pegs hit their holes and press them home. Reinstall the two phillips screws and reinstall the shoulder belt pivots.
Reinstall the light cluster.
Now for the fun...fitting the sunroof opening...cut the headliner 1" to 2" inside the opening (i.e. leave a good flap to start with!) Starting at the center front (mark the middle on the rubber molding and measure to the middle of the front edge of the opening and work both ways out from there...stopping at each corner to check for wrinkles and stretches) work the rubber molding into the groove in the metal molding, trapping the cut edge of the headliner cloth/foam in the process. (Hint: I intentionally left the first cut too generous until I started working on that stretch of folding and inserting the molding...it's a LOT easier to cut off another 1/4" than to have 1/4" too little material!!!) Be careful around each corner...it's a little tricky to fold and grab the material without wrinkles, but a modest amount of patience will see you through the job. As you get to the rear of the sunroof opening, trim out around the latch mechanism, but make sure to leave enough material that the escutcheon plate covers the cut edge completely.
After you get the rubber molding in place, reinstall the sunroof latch escutcheon, and you're done!
...it's really not as bad as it sounds...takes a bit of time and patience is all.
...oh, by the way...yes, you can take the headliner out and put it in the cockpit by bridging the passenger seat and dashboard and still be able to drive the car to take it to the upholstery shop if that's what you decide to do...but you'll have to reach under the edge of the headliner to shift.
No big deal...but looks a little weird...
...good luck...