I'm running a pair of Borla XS mufflers on my '73 Dart.
While they are nice and quiet for everyday use, they still are a bit loud at coming up to 2000rpm accelerating with part throttle.

The mandrell bent exhaust has an X-pipe which imo could enable the mufflers to make syncronised noise at around 2k rpm, probably increasing the sound level.

Considering putting an extra piece of deadend tubing in one side, or install resonators at the rear.