I have a set of valvetronic mufflers installed on my ST which give me the flexibility to have a quiet stock sound or a straight piped exhaust sound. These are the same mufflers that Savage Garage installed on their ST
This link is to a clip of what my exhaust sounds like in loud then quiet and back to loud.
I removed the resonator and installed an x-pipe as well and when quiet my wife didn’t even notice that I changed the exhaust. The only drawback to these mufflers in my opinion is when on quiet under wide open throttle they make a sound that sounds like a blower motor on high inside the vehicle. I don’t know if it sounds that same way outside the vehicle.