Used to run SH T#6 plugs years ago... were fine but at some point i had lots of broken wires and stopped using them.
Tried os, mccoy, rb, novarossi, sirio...
The best one, OS P3, tried it and will never try any other plug on any engine i might own in the future.
I used to be one of those guys who carried 5-6 different brands of plugs in my cases and would always try something else whenever i had tuning problems...this is wrong...different plugs work differently on weather, tuning, track,..., and if something is wrong...it's either the tuning or something with the engine itself.
Stick with the plug you trust the most and throw everything else away.
Sakura Zero S/Castlecreations