Just installed AWE muffler bypass w/ cat. Sounds like a mean **** I must say. I have a Viper SRT w/ headers, no cats and a catback w/ aftermarket bullet muffler.....and I must say, the 997TT isnt a whole lot quieter with this setup. Dont think Id recommend it for a daily driver, but for a weekend warrior if you like the in your face sound...can't beat it. I love it. To each their own.