I wouldn't use no name brands like Duraterm (this is the first I've heard of them). From what I've seen, Bosch or Beru are the best brands of glow plugs to use.

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.