Just picked up a 1997 Suburban 2500. I will be using it to tow a trailer full of ATV's and also my two b-bodies to out of town shows, one at a time of course. Like most people, i like to mod my vehicles. Im looking for opinions on an exhaust setup. one muffler, dual mufflers, 3 or 3.5" pipe, X-pipe... Im just getting into the research phase and have not seen much so far. Will modding exhaust help or hurt fuel economy? doesn't matter but if it helped, that would be a plus.