[SilverMk2]

The easiest way I know of it to pry it loose from the sunroof and bend it down in the middle so you can get it out of the track, pulling forward as you pull the middle down. The tricky part is getting it back in. The offical way to remove it is to remove the entire sunroof assy and slide it of the tracks.

 

[SilverMk2]

Also you have to remove the sunroof to do it. The headliner has a lip on the back that goes behind the sunroof panel.