Headliner fix?
 

Mine sags, no tears; just alittle saggy.

does anyone have a write up or have done a few?

bump?
has anyone done it without removing the whole board?

Yeah, I did it with a stapler. It is not pretty, but it works.

I tried one of the 3M spray adhesives on mine. Lasted great for about 2 weeks, then fell back down. I'm thinking of trying again with a different 3M spray adhesive, but haven't bothered to yet.

I think that removing the entire board is the only way to do it because you have to scrape off all the old glue to get the new glue to stick. Your local fabric store should have the headliner material in a bunch of different colors, my fabric store even had the 3M glue too. I replaced the headlined on my corolla about a year ago and it looks better than new with no sagging - the car is parked outside too. I followed the instructions on this site: http://www.wlsheadliners.com/tutorials/toyota-corolla-headliner/

Not sure if this will help but my son is planning on using this kit:
http://www.wlsheadliners.com/bmw-jaguar-volvo-audi-saab-headliner-kit-p-9.html

Check your local fabric store first. It cost me less than $20 for the headliner material and the glue. Plus you can see the color yourself.