I have a fully stock exhaust. At exactly 2k RPM I get a brief resonance hum, like a tuning fork. It happens at idle, moving, etc... Once the exhaust warms up it goes away. What’s odd is that it's exactly at 2k. The tach can sweep up or down it will make this brief resonance hum at the back portion of the exhaust. I have MREV ISO on the car, should I be worried if I bring it to the dealer with mrev? It’s clearly coming from the back portion of the exhaust.

Anyone else experiences this?

 

its vibration from the muffler. Try to look at the holders especially the one to the right hand side. There is a medal plate there that causes some vibrations.
Don't worry about your mrev. I don't think the dealer is going to say anything about that. Good luck.

 

will do, thank you oh drunken master