Age has done mine in and if your needing to replace them expect to spend $40.
Here is the tip: there is a strip of the old plastic left in the runner, you MUST remove this before installing the new piece. Remove the two torx screw holding the wind deflector and slide them out the forward area. If you don't and you go ahead and installed your new ones it jams your sun roof, now it won't open all the way.
Get some gel type super glue , an edge strip off the old accordion. For ease of insertion and removal take the J edge off, the part that works so well to hold the strip in the track and the reason you could not get the old strip out. Put a dab of gel super glue on the end and then slide it into the track and until it touches the old stuck track. Leave it alone and go post something on the forum, return and slowly pull the strip. Your old track should be glued to the modified piece and as you SLOWLY pull it out.
When installing the torx screw, put them into the strap, then the torx bit then into the hole. You don't want it stuck down in the head liner and thats a whole nother thread on magnet fishing.