...and my friend pulled an 80,000-pound 53' tractor-trailer with a single 4" exhaust with a muffler, dumped at the rear bumper. Uphill.
He then went to straight 5" pipe, no muffler, dumped at the rear axle and picked up some power there. After that, he went to MBRP stacks mounted off a Y-pipe in the bed, and picked up nothing, but he thinks it looks cool. All it did was make the truck obnoxiously loud, to the point that if he's giving me a ride home at night, I have him drop me off a couple blocks from my house. Not only do the Boozefighters have a propensity for calling the police anyhow, it's just plain embarrassing.