By owning a 99 Mustang GT and now the making payments on a 2006 Mustang GT has put me in a pretty unique position to review the two vehicles as it regards to CCW and security. Yes, IMHO a car is a piece of gear.
The Mustangs.

Besides the obvious styling changes between the two models, there are a number of carry or security related differences.
Starting in 2005, the 4.6L engine was upgraded from the factory to 300hp and 320 ft/lbs of torque as compared to the last models respectable 260hp or equal to the last models Cobra version. This gives the GT a very respectable 5.1 second 0-60 and sub 14 second quarter mile making it truly a retro muscle car. To put that in perspective, that's a faster rating than the Dodge Charger Hemi R/T by a full second and half a second faster than a BMW Z4. That's some get up and go from the badguys.
Unlike the previous model, Ford totally vamped the suspension to a more stable traditional sportscar suspension with full McPherson, not modified, front end, front and back sway bars, and oversized brakes. In no regard is this suspension retro and the car hugs the curves at speed with the best. The shifter, most frequently changed older model modification, was changed to a closer tighter shift for easier faster accelleration.
Though the styling is retro, it has some distinct security advantages. Those small portal back windows all but eliminate traditional blind spots in cars. The oversized hatch back reminiscent back window gives a major improvement in rear view. 4" larger than the previous model and the largest Mustang since the Boss, the back seat gains 2 cu/ft and the trunk 2 cu/ft taking the little pony car from road only to a vehicle you can haul your guns to the range in. This is especially true with a fold down back seat adding to the hauling space.
The retro interior with metal accented dash and over sized retro gages has some unique advantages. The first is they totally revamped the center console making it deeper with more room. It is now deep enough for a full size 1911 in holster with spare mags and tac light. The oversized retro gauges though a tad different thus taking some adjusting to the size, read more easy than the traditional small recessed gages. Unique to the GT is they are back lit during the day and the color can be changed to over 120 colors at night. This means like a submarine you can run red gages at night saving your night vision. Not relying on your night vision, the two oversized driving lights light up the road like a truck with light bar.
Don Johnson move over, a new vehicle is in town.
Tj