Putting the Cat and Resonators would help since a lot of the Raspiness is from no Resonators in most cases. I would call the guy back and see if he still has the mid pipe since legally he cannot sell the car with modified Emissions, it is against Federal law to do so.
Putting the Stock Cats and resonators back on would tone it down a lot. American Muscle has A MBRP Cat Back exhaust that is supposed to sound pretty good for under $600 that is all Stainless.
2013 V6 MCoA, Performance Package, Security Package, Comfort Package and Electronic Package.
Mods OEM Backup Camera, BBK Shorties, FRPP Cut and Clamp X-Pipe, Borla Touring A/B's, Airaid CAI, Axle Xchange 2 piece aluminum Driveshaft, Koni Sport Shocks and Struts, Vogtland V6 Leveling springs, Ford Racing 302s wheels wrapped with Continental 275/40 19's, 14" Brembo Front Brakes, 13.8 GT500 Rear W/O Backing plates. 2013 F 150 FX2 With a 6.2 Boss