I bought bullitt mufflers off a guy who has an 08 for 250. Them Plus an X-Pipe with Ford Racing Shorty headers and I couldn't be any happier with the sound! Slightly deeper than stock, but very smooth. No back fire or rasp at all.
2006 Mustang GT Premium. Bullitt Inspired
4.10s, Ford Racing Shorty Headers, Custom X-Pipe w/ High Flow Cats, Bullitt Mufflers (off an 08') Ford Racing 62mm TB, K&N CAI, Predator Tuner w/Custom Tunes, Steeda Pulleys, Roush Scoop and Louvers (won in a poker game!), Eleanor Grill, 8K HIDs, Smoke Turn Signal Housings, Side Markers, Taillights, CDC Blackout Panel, "Power by Ford" Shelby Emblems, Ford Racing Lowering Springs 1", 18" '10 Premium Wheels