Not to get too far off topic, but i don't think you can really tell what that GP sounds like if it has the hoses hooked up to the exhaust. On the other hand, I kinda liked the big-cam idle. Turbos do sound good though. European 6-cylinder cars usually tend to all sound fairly similar for the most part, usually really smooth and refined. Same with some japanese engines.
Figure this for a built 60°V6 (not a 3400, but a hybrid engine with the iron heads) for the sound 3rd through 5th inside the car..
http://www.turboz24.com/Files/Exhaust_1.wav