I just finished a headliner replacement and sunroof repair on my car.

Wow, what a ton of work, but I am happy with the result. It isn't perfect, but it is a LOT better than rags hanging from my ceiling. Having the worst allergies I've had for years did not help.
Also, I have the sunroof working again - The issue with mine was that one of the slide-arms broke. A quick trip to pick and pull and $8 later I was on my way.

Some hints for anyone doing the headliner repair-

-Have spare trim hold-downs (plastic ribbed one-way bolts) on hand because the ones you take out will be very brittle.
-It is a really REALLY hard job to get the #@%# headliner board in and out in one piece.
-While working on the other pieces, you can put up the top side trim (where the o-shoot handles are) to help secure the headliner.
-Contact cement (used for the metal sunroof panels) works to repair the cardboard headliner board. Try it. much better than duct tape.
-DO get the 1/8th inch material. I even had doubts about the 1/8th stuff binding, but it did work.
-Make sure you reassemble the sunroof with it in the vent position!
-When applying the headliner adhesive (I used 3M #80 spray, which says "may be used for headliners", not the 90, which seems to be more finnicky), let it sit for a few minutes before trying to adhere the fabric. The longer I waited to press down the headliner material, the better it stayed. The FAQ says 30 seconds is peak time, but I found that more like two minutes was good. Two minutes when it was windy and around 70F and six or seven minutes after the sun went down.
-Don't overspray glue onto your new headliner >.<
-Possibly I missed where the FAQ talked about it, but I did not leave fabric loose around the sunroof, on the headliner board. Consequently, I have a gap between the sunroof and headliner. It's noticeable, but not too bad. It looks like you need to leave a few inches (3-5) to put over that gap and tape down with double sided tape - I remember reading something in the FAQ about "butyl tape". Maybe it could be clarified.

-To get all the rear trim apart, you will need a lot of patience and to unhook the rear seats. It's worth it. Taking out the front seats made a difference for my car. It's also a lot cleaner now that we did that. The board WOULD NOT come out with the seats in there (one was enough to get it out, but both was better).

-It's a long project. You'll want to plan a three-day weekend at least. And it will require finesse, swearing, sweating, and probably a six-pack or two.

Good luck, happy bricking, and all that.
-Will
--
1990 740 Turbo, on its way to stock specs, maybe beyond