Replaced full set of mechanically broken plugs on a MB Vito 115CDI using the Laser 5205 http://www.lasertools.co.uk/item.aspx?cat=1083&item=7119
Broken glow plug removal kit. Reamed out the carbon fouling from the aperture using the Laser 5154 tool.
Installed them with a coating of ceramic anti seize paste.
I have used these Bosch glow plugs on several different cars and none have failed so far. (Oldest was 5 years ago)