Danny Dirt used to use SIG glowplus, at least mostly...sometimes OS. He was leary of idle bars, having had one ruin an engine once. Is there some reason you don't want to use Thunderbolts? I don't know who makes SIG glowplugs, but would like to. Most LHS can get Zinger glowplugs...they appear to be the same as a Thunderbolt, with some cosmetic changes, and work the same. K&B are also good stuff, all made by Ohlsson Corporation. I've never had a problem with idle bars, but mostly use 4-cycle plugs these days.

Steve