I saw those today too and put in my ebay wish list. I may try, as long as no risk they will shatter and leave pieces in the pre-chamber. Since I got a set of Craftsman ratcheting box wrenches, removing the glow plugs is much easier. They have small click increments that work between the injector tubes. I usually run a tap thru the holes (turning with my fingers) to clean carbon. You don't need the custom glow plug tap.

In my limited experience and memory on two 300D's w/ pencil type glow plugs, the bad ones I removed were Bosch and don't recall a failed Beck-Arnley that I installed. I bought a large set of the later off ebay years ago. Don't know how old the Bosch ones were. I think none last forever. My son called last night and said the 84 300D he just drove back to school has been requiring 20 sec to crank and the glow light stopped coming on. I recall that means that at least 2 glow plugs are bad, or could be the relay. I checked all with a multimeter before he left. He said it has been cold, but that is relative in San Diego.