I assume you have one or more bad glow plugs which is the reason for your need as they are not a "routine" maintenance item although some folks are replaceing them just because the ceramics can fail and lose fragements that can cause engine damage. Comments:
1. I suspect they may be a warranty item but you are well past the end of the 05 or 06 model year warranty unless you purchased an extended warranty in which case you would need to check that warranty's terms.
2. new ceramic glow plugs are no longer available from DCJ although there may be some new old stock around somewhere. I do know a few members (ex. geordi IIRC) have used ceramic plugs available.
3. the DCJ replacement "kit" of 4 5v plugs and a controller (68090434AA) runs ca. $125 last I looked but requires a dealer ECU reflash ($100 or so) or an update to your GDE flash ($50)
4. the "drop in" (no controller or flash needed) option is the Etecno1 7v glow plugs GX3123 (
http://www.dieselglowplug.com/) - best route IMHO if you need to or want to replace the ceramics.
See
viewtopic.php?f=5&t=56696&p=630729&hilit=glow+removal#p630729 for how to. You will need an intake elbow gasket (5066946AA). Just get it from a local dealer, shipping will eat up any mail order savings.