Inline 6 sound: ITBs vs exhaust vs cams?

The M52 sounds very beefy from 0 to 4000. Almost like a V12. However, hitting the rev limiter is not as enjoyable because from 4000 and up the sound is too buzzy, very a straight piped V6.

So, I was wondering what’s the best way to solve it and turn the high RPM buzz into a proper howl. Make the sound deeper, essentially.

The first item that comes to mind is ITBs but thats probably on the exp side.

The other thing was cams. To make it more supercar-like in profile, like an M1. But that’s gonna take some of the low end torque.

Another thing was the silencer, but theres hardly anything good you can find on YT to see how it sounds.

So, anyone to chime in? Any proven way to make the m52 sound deeper at high rpms?