i like how they look. i like things to be balanced, its part of my job. i also think they would help spread the noise to either side of the truck; another bonus! i can't see how they would be a power gainer any more than a shortened exahaust, since the flow is still restricted up to the muffler.
i loved the look and sound of the side exiting true duals on my 84 chevy truck. it will definitly be added when i get my diesel, even if not a power gainer....