I've done axle-back swap of the stock '11 GT mufflers in favor of the Ford-Racing (GT500) mufflers. Well worth every penny (and it's only ~ $250 for the pair). The exhaust is loud enough to enjoy...but not too loud to enrage the neighbors. And no drone on the highway. Looks wise, the tips are larger than stock and nicely fill the rear valence cut-outs. It's an easy swap; just unscrew the stock muffler clamps and all the hangers are in the same location.

 

I'm interested in getting those. Where did you find them for $250? Thanks

 

If you desire just a bit more sound with the GT500's, removing the resonators is another low cost mod. Ran me $70 at a local shop and I love the sound.

 

I got mine for $255 from latemodelresto.com

 

I got mine from American Muscle...and used a discount coupon my son had.

 

I got mine from a guy who had his Shelby "Super snaked"
Paid $150 & they only had 5mi on them.......sprayed them with black high temp paint so they'd blend in underneath.