Check out Borla as well. I went to several local Cars & Coffee's and almost all the Mustang owners were happy to let me listen to their exhausts. Just like speakers, sound is subjective and it really comes down to your personal preferences. Magnaflow, Flowmaster, and Borla are all very good manufactures. I was looking at all of them until I settled on the Borla S-Types.
2013 V6 Auto Premium | Sterling Gray | Pony/Comfort/Security Packages
Borla S-Type AB | Airaid CAI | SR Performance STB | JLT Oil Separator
MPT Tuned | SCT X4 | MMD Classic Louvers | Roush Upper & Lower Grilles
BFGoodrich G-Force Sport Comp-2 A/S Tires | Windows Tinted @35
Flux Capacitor v3.2.1 | Mr. Fusion Generator v4.2 | DB Hover Conversion