Enya plugs are also very good but the Enya 3 is too hot of a plug for the OS .46 unless you plan on using 5% or less nitro. (Enya 3 is a hot plug mainly designed for use in 4 strokes or low nitro engines) You are better off using an Enya 4 with more than 10% nitro (http://www.modelrec.com/catalog/mrc/index.jsp?cat=45) The OS 8 is a hotter plug than the OS3 which is why I recommend using the OS3 when you are using more than 10% nitro. The OS8 will run fine with 15% nitro but may not last nearly as long and you may have some detonation problems with 15% on hot summer days (especially of engine is still new and tight)

Luckily for you the OS .46 is a very well mannered and easy to tune engine and almost any plug will work with (assuming it isn't too hot). If you want to save money try a K&B1L or tower hobby plug but the OS plugs and Enya's last a lot longer.