Well, I can help you with info about the Magnaflow P/N 12388 direct weld-in muffler. It has all of the same dimensions as that of the factory muffler, but it's a flow-through design unlike the factory unit. You can see right through it. Sounds pretty good, doesn't it?
I'm sorry I did it.
The factory muffler has a raspy sound to it at large throttle openings. I nearly scared a guy in a Miata off the road when I passed him because of the loud, raspy factory muffler. It added to the character of the Raptor. The Magnaflow is smooth. Too smooth. That raspy characteristic is gone now. I wish I had it back.
No advantages to the Magnaflow. No MPG increase, no power increase, no nothing. Just a deep, smooth, and otherwise unremarkable exhaust note.
I'd stick with the factory muffler if I were you. I wish I had.