Congrats on the car! As I have recommended in all exhaust threads I have posted on, I would do MAC all the way on the V6. I have spent hours and hours researching exhaust, listening to clips and the comparing price; MAC is the deepest and throatiest out there for the V6. If you look on YouTube you can find many clips with the Y-pipe and MAC mufflers and they are deeper and throatier than any of the others and that's without a H-pipe. I bought the MAC GT mufflers and am having a custom H-pipe and pipes going over the axle done so I can be louder, throatier and deeper. I will post results as soon as I get it all done. The quality of the mufflers is great and the 4in tips are to die for visually. That is the product of my hours of research and is what I recommend for you.
2003 Lamborghini Murcielago
2007 V6 Mustang (manual), Hurst/FR short throw, MAC dual exhaust, custom H-pipe, chin spoiler, GT front bumper, billet aluminum grill, GT500 rear bumper, GT500 wing, FR windshield banner, FR strut tower brace, LED interior lights, sequential taillights, FR side markers, slotted and drilled brakes, 93 Cobra teal painted (and cleared) stripes, etc.