Dale Amy
February 4, 2011

Well, I managed to avoid getting arrested, and that's no small accomplishment when turned loose for a day of infantile frolic on the streets of Detroit in a 624hp '11 GT with humongous "Supercharged by Ford Racing" billboards on its burnout-pockmarked rear quarters. Stealthy, it ain't.

The crew at Ford Racing put this graphically extroverted Kona Blue coupe together to showcase some of its available late-model parts and mostly to highlight their new 9-psi, twin-screw Coyote blower kit. Thus its rear-quarter billboards; thus my fear of imminent imprisonment.

Those initial worries of maybe attracting just a bit too much attention were compounded once I turned the key and the Coyote immediately barked its current location coordinates to most of Dearborn through FRPP's new (M-5230-MGTLA) Sport axle-back exhaust kit. So now Smoky didn't even need to see me to hunt me down.

But after spending a few urban and freeway hours in their sonic embrace, I have to confess that even as the recognized curmudgeonly old fart around these pages, I've just flat fallen in love with these mellifluous mufflers, which are pretty vocal without being obnoxious in any way. They are not boom boxes (they seem to sing in a higher octave), nor do they drone at all on the highway. On lifting the throttle, they emit a playful cackling back-off burble the likes of which I haven't heard since prior to the days of catalytic converters. Windows down or up, they are truly symphonic, but like this car's graphics, not exactly stealthy.

But maybe I should talk some about the blower, right? In fact, Ford Racing is now offering two levels of intercooled supercharger for the new 5.0-liter. First up is a variant (M-6066-MGT525D) good for 525 hp at 6,400 rpm and 470 lb-ft at 4,200 rpm by way of about 7 psi and a calibration for use with 91 octane fuel. This base system also brings a 12-month/12,000-mile warranty if installed by a Ford dealer.

However, the top dog is this car's 624hp version (M-6066-MGT624D, with 536 lb-ft at 4,700 revs), which huffs out 9 psi of boost while requiring 93 octane for that full output. This one has no warranty, but both versions are 50-state legal; are based on Whipple's proven, quiet, and highly efficient 2.3-liter twin-screw assembly; and can be had in either black or polished finish.

Numbers are fine, but those of us who have been through the ongoing evolution of Mustang forced-induction systems know that even four-figure power is relatively meaningless-especially for a street car-if it only shows up within a narrow, high-rev band. Have no fear: Like most screw blowers, this system comes to life at the slightest nudge of throttle and feels as linear as gravity right up to the 5.0-liter's stratospheric redline. Leave the traction control on and this salvo of Ford Racing firepower is manageable by even the most fumble-footed newbie. Turn the nanny button off, however, and you'd best be paying attention, because even this coupe's generous rear skins could be overwhelmed in the blink of an eye-over and over and over again (so I'm told).

Yet FRPP's included calibration is honed to factory-civilized perfection, with none of those driveability warts and hiccups that used to drive us nuts and limit our supercharged 'Stangs to occasional-driver status. Man, we're spoiled these days. These are the most seamless, well-mannered, and unobtrusive 624 horses you'll ever encounter, making this a ride that could easily be driven every day (though winter might get interesting), while always delivering a grin and the distinct possibility of incarceration.