Truth be said I have not removed it yet. I took a look at one plug at 28k miles and did not remove the trim cover. My car has 36k and I am going to need to figure this out soon also. IIRC when I tried pulling the cover off I also had trouble with tabs breaking on the lower holder so I stopped and just checked on one plug.
I'll take a look at the parts catalog and see how expensive that lower tray is and if it's not too expensive I'll just replace it when I do the plug change.
The P/N is 03H971803 for the lower conduit; and 03H971839 for the upper. The lower runs ~$15 and upper ~$10 at 1stvwparts.com. There are same P/N's with a "C" at the end also; listing for ~$10 each. I'm not sure what the difference is; ETKA just says "alternately use" 03H971803C.
There is a recall campaign for the coil packs; if you are doing the plugs it might also be a good idea to replace those coils as well. Check with your dealership; they might put your new plugs in for free with new coils.
Modified by TheCentralScrutinizer at 3:50 PM 1-23-2010