My "middle muffler" is a Cherry Bomb glasspack!
Still have the factory cat at this time.
The GM F-Body MagnaFlow Stainless muffler needed 'something' ahead of it to take out the ricey barking/nasty backfiring sound, even with the ANSA Stainless Resonator Tips behind it.
The 'bomb' worked as figured. Any glasspack/resonator installed ahead of the muffler, behind the cat, in the long section of exhaust will take away the annoying tones of a free-flow muffler at the rear of the car. The exhaust shop explained that the location of the muffler is the cause of the unwanted noises. Placing a psuedo-resonator in there worked perfectly.
The car now has a much nicer sound and the components are suited to the climate I live in.