[mutant chicken]

I would imagine it would be like my wife's Tahoe, if it weren't for the info center you wouldn't be able to tell that the engine had dropped to four cyl. mode. The power is still there when you jump on it, but you can't tell otherwise. As far as exhaust note I'm not sure, we haven't changed the exhaust on her Tahoe yet, and with the stock exhaust it is not noticeable.