well put.from where i stand ive got some first hand know how on this subject.being a fabricator by trade ive built a few different exhausts for my car.if nothing else i can tell you this...that on my setup (street driven 340 with tunnel ram) there was a big difference between a 2.5 true dual full length system with flowmasters to a 3" x pipe system with straight through type mufflers.according to the butt dyno it felt like you pulled a cork out of the exhaust.adding an X or an H (ive built both)to the 2.5 system helped some,but ditching the flowmasters helped more .if the OP decides to keep the 2.5 system id look into swapping in some magnaflows or ultraflows.
