My 2+2 had hockey pucks and a full cage and stuff would buzz in cabin at highway speeds, like the glovebox or where two pieces of hard plastic rub against each other. My '13 Mustang and pretty much every modern/stiff car have similar buzziness.
Buy a roll of Butyl tape and stick a little between buzzy panels until the buzzing goes away.
Buy a roll of Butyl tape and stick a little between buzzy panels until the buzzing goes away.