RE: Exhaust
As complicated as modern cars are, I'd be very leery about altering any of the settings or equipment. You gotta figure that Chrysler has spent multiple millions of dollars figuring out the "correct" settings (probably mainly for antipollution-law compliance and gas mileage). I realize some people here are actually involved in the automotive industry, but personally, I don't know enough about modern cars to even want to attempt alterations.