Its not really "meant" for the GT, its just the stock diameter for it. My long tube headers are 2.5, and it is meant for the v6. I am doing all my exhaust the same diameter "2.5", so it may help with rasp, though I am thinking of throwing the 2012 gt500 mufflers on the back and they are 2.75, but out back it wont hurt it any.
2014 3.7l Auto Oxford White
Mods: Cervini Stalker Hood, Roush highflow upper and lower grill, AirRaid CAI, LMR strut tower brace,Mac LT headers,Mac Prochamber, Kooks Highflow Cats,Dynomax Race Bullets (resonators), 2.5 o/a pipes, 2011 Gt500 Axlebacks, MPT 93 performance tune.