Wagons are sort of easy to change out, if you can find a good one to install. I've done 2 in the last 2 years. You take apart all the roof trim, carefully remove the dome light and the sunroof trip, and walk it right out the back with the help of 1 or 2 others.

Sedans are a bit more of a challenge. The interior work is the same, roughly, removing all roof handles and dome light and so on. The seats go back and the headliner drops and turns and bends just a little to go out the front passenger door.

Material can be obtained at fabric stores, the old headliner panel is scraped clean of crumbling foam, and you spray everything liberally with 3M "77" adhesive. Clean clean hands too! Press the new fabric in place and then trim off excess around edges and sunroof hole.

A real repair in place, honestly I have no better suggestions than staples and fasteners mentioned here. It's a pressed-fiber sheet, sort of like heavy cardboard, so light fasteners can be used in it until it fails again.

These headliners are probably one of the few big failures of the 740/940 series of cars. They're all going to come down one day.

--Rob