UPDATE (5-MAR-2024): TLDR - I believe the heat shield by the center support bearing is/was the cause.
After dealing with this periodic buzz for almost 2 years I finally decided to really look into fixing it last weekend. I tried to clamp a few of the heat shields that wrap around the exhaust, but no change. Last weekend I was under there tapping the heat shields all over and it seemed like it was coming from the foil type shields that follow the contour of the floor so I started putting some foam in strategic places to dampen the buzzing. After about 30 minutes of messing around with that, I think I found the actual cause. There's a heat shield that protects the center support bearing for the driveshaft right above the resonator. When I tapped on that I heard a buzz. I thought, hmm, interesting, what is that hitting? Turns out that heat shield was close enough to the center support bearing when it hit a resonant frequency, it would bounce (buzz) on the metal bracket that retains the bearing. I put a couple washers at the mounts of that heat shield to space it away from the bearing. So far, with my drive in to work today the buzz was not there. This afternoon will be the real test since getting on the highway from work is where I noticed it almost 100% of the time.
Original Post Below:
On my 18 Sport, I notice a buzz when the engine gets to about 3000-3500rpm.
I really feel it in my feet and it sounds like something is vibrating (like a panel or heat shield).
I did turn off the fake engine noise through Forscan and that seemed to reduce it, but that may have been my imagination.
I plan to get under the car (maybe this weekend) to check, but looking for any thoughts.
It's certified for another 10 months, so I could bring it to a dealer, but I'd like to know if it's common (or at least known).
Anyone else experience this?