I have a 1SS with NPP; I just recently went over 4K on the mileage and have noticed difference in the exhaust note (louder). I started to notice it as I neared the 4K mark, up until then it was fairly quiet after I let off the throttle. Now, don't get me wrong, I like the sound, but, it is just a bit unusual that it would get louder all of a sudden.
Now my question for SS owners with NPP; is this normal?
