Plugs
Rick,
Horizon Hobby has them in their catalog, they are a Hangar 9 product now.
I have a P-80 and am using an Enya 3 with great results, I get immediate starts. I went with the Enya because it has a nice ball on the end that hooks into the plug cap very securely, in addition to being a very high quality plug. I think Bob Wilcox is recommending the OS A3 which also works great, is cheap and lasts a long time.
I think all you really need is a good standard hot plug. Most important is the prep, you need to pull out two coils about 1/8". That more than anything will insure a fast, positive start. Beyond that to the best of my knowledge any quality standard RC plug will work.
Gene