The reason for making the car capable of being noiser is because it is childish and silly.
A perfectly sensible thing to do in my view.
But then, I'm regressing back into my early 20s.
Adolescence is but a few years ahead, when I can be really silly!
Krazy Horse do a switchable system for the 3.7 Roadsters, I had a good look underneath and the pipework & valving was very well made
It's vacuum operated (intake manifold) and is switchable on the move from a little wireless remote, defaults to off, so each time you start the Mog it's in quiet mode
The hooligan in me was tempted, but for a Yorkshireman it was a little too 'reassuringly expensive'