why would you want a car of the srt6's class to growl/cam at an idle. it's not a muscle car. a mclaren f1 is almost unheard when it idles. the veyron doesn't even make that much noise and it's a w16. just some ideas for consideration. when your going down the road is a different story. i'm considering the catback system for my '04 6-speed coupe, only because i want the extra hp and noise during acceleration. go outside and look at your muffler on your stock system. there should be an "amg" emblem stamped on it: the highest quality you can get from mercedes. and trust me, the srt6's sound is much more aggressive and raspier than my 6-speed. plus, you have the light whine of the supercharger.