I love that popping sound on the decel. I wouldn't ever want to tune it out. I just drove my G8 4,000 miles round trip from Seattle to Phoenix, AZ and back and it never once bothered me having the popping noise. I even averaged 23.5 mpg with the AFM tuned off the whole trip.
2009 Pontiac G8 GT Liquid Red Premium/Sport, 20" MRR GT1 Staggered wheels, Superchips Cortex, Vararam OTR, Solo Axle-back w/ 3.5" tips, x-pipe, 20% tint all around, 6000K DDM HIDs, LED fogs, TS|S Fender Badges, GXP Diffuser, Spare tire kit, Maverick Man CF Spoiler, Blacked Out Front Grills, Belkin Bluetooth Audio