Yesterday I checked out the Magnaflows at a good muffler shop that does custom work. Told them i wanted slightly louder-deep sound but not the "weed-wacker" sound at cruise. They recommended the 'Flows over the Flowmasters for the sound I want. There is a difference between the sound of the X-pipe versus H-pipe.
And go with duals, it's the look of a muscle car. And ask the shop how they will do the cut-out, air saw, file or dremel down the edge for a smooth look.
I've heard this adds about 10 hp.
Good Luck and enjoy the
Stang !