I have a 2012 Road King. I put on a S&S air cleaner, V&H Power duals and Hi Output slipons. I haven't had it tuned yet. I went for a ride, it started nicely, accelerated nicely, no deceleration pop, and when I got home I checked the plugs the next day and they were brown with a touch of white! So does the ECM make the adjustment using the O2 sensors? or maybe I'm color blind! I'm waiting for my SERT to get the best tune, but this is interesting to me.