Like I said when you push down on the throttle you can hear the muffler, but it smooths out to be non existent once your foot is off the pedal or when your barely touching it to keep the car at the same speed. However, once you shift and the car goes back down to a lower rpm "mainly 2k" the noise and vibration becomes more apparent. But once back to prime rpm driving rpm for that certain gear "3.5-4k in my opinion" then the drone and vibration is gone once again. I'll take a video of me driving, with the camera inside the car tomorrow with it aimed at the rpms, so you can hear how it sounds with the windows up and no music down at certain rpms and when shifting.