Exhaust opinion

Walker makes a single inlet dual outlet muffler. They were used on F150s from the 80s. When I used to work at an exhaust shop we replaced a lot of them. On the Fords, the dual tailpipes ran out the same side but you could run the tailpipes out both sides pretty easily. That would be much easier then mounting dual mufflers on one side. Walker probably also makes a dual inlet dual outlet muffer.

If all of your pipes are mandrel bent, I don't think you are leaving much on the table. It just depends on if you like the look of one tailpipe or if you want 2. I always heard that a 2" mandrel bend pipe flows the same as a 3" pipe that was bent on a traditional bender.(crimped bends)