I have BBK longtubes and catted X pipe. Mufflers are Ford Racing sport axlebacks. It was very loud . I installed a pair of GT resonators that I had sitting around, and it toned it down to acceptable levels. But there is still rasp in the 3500 rpm range. And you are not going to get rid of it. This is a 6 cylinder.But the sound at idle, and during cruising speeds, is as good as it gets IMO.
And the added mid range torque, was definitely worth the effort.
2011 GT. Grabber Blue. Procharged. 3:73 manual.Billit LCA's. Corsa Extremes. GT 500 wheels. Racemaster DR's. T-56 Tremec. Dynotech DS . Centerforce DF. American Racing headers/high flow cats 560 rwhp.Donny Walsh tuned
2012 Pony Package. Race Red.3:31 automatic.BBK longtubes and catted X.FRPP Sport axlebacks. BBK throttle body. Dynotech DS. Brembo wheels and tires. Strut tower brace. Airraid CAI. Bama tuned.