Mine sounds pretty similar to the SLP Loudmouth, even a lot of people said it sounds like an LS1 Car, Mustang, or right inbetween. But I also have the 4.8 
I have Just stock Manifolds, no cats, Flowmaster Super 40 dualed out but with no echo tips (Kinda like dual split rear turn downs, old school muscle car style) , I took them off because it made it a bit more "poppy" and truck like.
Ive heard cowl327s truck in person on here, I dont know if hes modified it since, but it sounded like a camaro or a vette.
2012 F-250 XLT/FX4 RCLB 6.7 Powerstroke
H&S XRT Pro Race(550hp/1100tq)/ 4" flopro exhaust/H&S EGT kit/SPE Full diff unlock/S&B CAI/H&S motorsports upcharge pipe kit/ DPF,CAT,EGR,UREA Deleted/Icon 3.5" Lift-Vs 2.0 shocks/PMF DSS w' Bilstein 5100s/Icon Adj Track Bar-upgraded steel bearing/RIGID LEDs/Kenwood DNX570HD w/idatalink maestro/Hertz5x7s/Memphis 12" slim/500.1 JL slash amp/Recon f250 led emblems