Just put on a nice intake system (pod box) with no rear muffler, leave the stock headers and everything on.
Under load or when you are passing someone it will sound like a rocket nice and loud, but when you back off, it will still be nice and quite. I hate most exhaust systems on 6's. The stock exhausts sound mint when passing and stuff.
I dont know about most of you guys. But doesnt the drone bother you at all? I have a custom exhaust on my statesman thats nice and quite untill you open up and then its really loud.
Here is the old exhaust that was on before all the honeycomb broke.
YouTube - VS Statesman V8 5L Exhaust