Well, since I did not get a response, I went out and put in just two E3 spark plugs in the primary position. I instantly noticed a smoother running bike.
I went with only two for about 2 months and thought if this works this good, changing the other two will only help.
I noticed a much smoother engine, a lot less backfire when coming down out of the Rockies, and the gas mileage was really better.
My girlfriend has an 06 and I have an 07. She has been holding out on the change, but she cannot get the gas mileage I have been getting and the other day we were sitting at a stop light and my windscreen was not moving, while hers was shaking like an earth quake. Needless to say, after that visual, she has come over to the "good" side.
Oh, one other thing, you will notice an increase in pulling power and it will be easier to move the bike when it is all loaded up for a camping trip.