So I was able to test drive a stock ISF today and I noticed that once the car was moving at around 65-75 MPH the exhaust note changes and gets really deep and loud to point where I could feel it in my ears. I'm just wondering what makes this happen and I could get a similar effect with an M3.
Former e92 M3 owner
Relapsed M3Post addict
Hopefully getting back into another ///M soon (or P-Car)....P-car as in Prius.