If your looking for performance AND sound, then you need to start with the engine and go back. It'* like a common rule for modding exhaust systems. You have to start with the manifolds. With the 3800, it already has one "header", but the front manifold really sucks. So, you would only need to replace the front one. Once that is done, convert your down pipe to a 3" with a matching Magnaflow cat, and base the rest of the exhaust after that. Some go with Borla, or Magnaflow or Flowmaster for mufflers. dual out or single out, does have a little effect on sound, but really, its all up to you on what it sounds like. Search Youtube for different 3800 exhaust sounds.
And remember, what sounds good to one person may not sound good to you. Everyone'* ears are different.
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