99 Suburban Vortec 5.7. Currently it has a dual exhaust with a Flowmaster (40?) muffler and I hate the drone on the highway. I had a 95 Suburban TBI 5.7 in the past with a stock exhaust except for a Magnaflow muffler and it sounded better when driving on the highway and I'm about to move so my commute will be at least an hour each way. Will I lose any HP/TQ/MPG by going back to a factory style single exhaust? I mean it is already slow and gets poor mileage anyway... I want to do away with the dual exhaust because I'd rather the exhaust come out on the passenger side like stock vs the two pipes out the back - if I leave the truck running while I'm loading stuff in the back I can smell the exhaust which is annoying.