I had a Stage IV ported Eaton for a while with a 2.8 upper pulley, then went with Whipple (they sponsored me) and have been extremely happy. It is loud when I get into boost, but normal driving it is quiet like stock. Except for the sound of my exhaust. I get a ton of compliments on how well my car sounds.
We have done KB mods to cars as well, but they don't produce the HP as advertised.
If you want a great sound, I recomend the Procharger kit or Twin Turbo. I love the Procharger sound.