But, all things aside... like the various plugs in various heat ranges from the various manufacturers:

When you consider that (in North America) 90% or more of the engines are designed to run on 5% to 15% nitro/18% oil and are set to run with this fuel with a medium/warm plug - you will, after testing the various plugs on the market also come up with what works well irregardless of what the plug heat range is claimed to be.

FOr instance, after running dozens upon dozens of engines with many many plugs in my personal experinece its very VERY hard to beat the OS #8 for performance, and durability. When I buy a new engine, I put in an OS #8 FIRST knowing full well it is more than likely going to be the proper plug for the engine. Yes, there are exceptions and in some cases another plug will perform better. But, I imagine most of the readers here are into sport flying with the more common engines available. There are plugs that will run similarly to the OS, but they (again in my experience) do not last nearly as long. Similarly with the OS F and 4 strokes. Some work as well but do not seem to last as long.

In the end, like engines, there are many to chose from (plugs that is) and some may like a Fox, some the OS, etc etc but all We can offer are the real world experiences we have right?

AJC