With normal driving you really won't hear any difference. But when you floor it, you will get a good "growl" from under the hood.
You won't hear any difference between the Gibson SS and Aluminized systems.
The Gibson Single has a very good sound. Like the Volant, you won't notice too much difference until you get into the throttle, then you can hear it. Its a good sound, not raspy like some systems. Also it has very little drone, unlike many others.
I have had the Volant and Gibson SS systems installed for about 10,000 miles. I think it is the best combo you can have on the Armada.