When I installed the 60 series flowmasters on my 2001 Mustang GT it sounded great. It was real throaty, and the 2005 and above models sound nothing like that. I guess because the mufflers are closer to the rear of the car. Is there any way to install flowmaster underneath the 2012 Mustang GT? Or is there any other exhaust system that would make my 2012 5.0 sound similar to my 2001? Thanks in Advance.

 

You nailed part of it, distance of muffler from engine is a part, having 4 smaller valves, instead of two larger valves is another.
Look at cat back kits not axle backs, don't be stuck on trying to get a Flowmaster up under the middle as I don't think there is room.(Flowmasters are kind of bulky)
I've got Pypes mid muffler on an 07, that everybody I know says sounds great, they used to have fitment issues, not sure if they cleared that up or not, but even though it took me hours to get mounted just right so nothing rubbed or clanked the sound was worth it, to me.
Have not looked much at what is available for 11+ cars, but I think I have seen some mid muffler type of cat backs.
Good luck, Google is you friend, and sound clips also help.

 

What AK recommends for cat backs is very good. And he says no axle backs; I have a varying opinion. I put Roush Axle Back exhaust on my 2012 and it has an incredible sound.
Nice deep throaty sound with some rumble, really made the car sound totally different and mean!! Easy install also.
I was thinking about the GT500 axle backs before I listened to the sound clips on Youtube,def check those out then decide.