As mentioned, quiet is relative. Some people's definition of "quiet" will give me a fucking headache after 10 minutes of being in the car. To me, quiet is stock exhaust. I ran 3 long ass 3" glasspacks and then a magnaflow wide open 3" muffler on the miata. Supposed to be "quiet". Quiet my ass. It was deep, but still loud, and still gave me a headache on long trips, and was loud when wide open, albeit deep and not-raspy at all.
I ended up putting the stock muffler back on, and now it's quiet as it was stock. I'll add an e-cutout per a couple forum members advice as that will best suit my needs. Quiet all the time, but loud when wide open. I'll probably set it up with an override switch as I can make a good 250whp with the stock muffler and it's still quick, but open when I need more power. Right now there's no cutout, so the stock muffler is killing top-end power. Hopefully a cutout will be going on very soon.