Honestly this single 5" mbrp cuts engine noise so much it is shocking. 2x36" mufflers would make it damn near silent.
i have a 5" silver line muffler like yours but dumps just behind the back of the cab. with the twins it really keeps the drone down but in the back seat there still is some when towing. at some point i may have to run it all the way out the back though. always wanted to do some flush mount boat flappers in the bumper and run duals. use little magnets when the truck is off so they stay shut, then open when you start it. more of a pipe dream now