The NON "R" plugs will work but can cause unusual problems. The "R" is for resistor and is used due to the design characteristics of the CDI (capacitive discharge ignition). I've used them with no noticable problems but you are better off using the "R" plug, especially if you are having any other issues with the way the bike is running. Don't add an unknown to your problems by using the non "R" plug.
The BR8ES is a very common plug, use a 7 if you are really bogging the engine most of the time, a 9 if your WOT alot. The 8 is the best median for most riding conditions.