One-hundred-fifty-five mph top speed. Zero to 60 in under five seconds. Run-flat 40-series tires on 20-inch forged alloys. $39,995 Base msrp. Not numbers you'd normally associate with a Jeep, but those are the basics for the newest Grand Cherokee, the SRT8. SRT, also known as the Street and Race Technology team, credits the 1997 Grand Cherokee 5.9-liter V-8 for inspiring its latest project. Since it began in 2002, SRT has produced 11 performance vehicles; before now, our favorite was the 500-horsepower Ram SRT10.

The formula is fairly simple: start with a 6.1-liter HEMI V-8, rated at 420 horsepower and 420 pound-feet of torque, then strengthen the full-time transfer case and enlarge the dana 44 rear axle to get all that power to the wheels without exploding. Next, add four-piston Brembo brakes with 14-inch rotors, reprogram the ESP (to allow the driver to use wheelspin and throttle control when needed), use Unique anti-roll bars, lower the vehicle an inch, and put monotube Bilsteins at all four corners. The result is a Jeep that thinks it's a supercar. At the track, our SRT8 ran to 60 mph from a standing start in 4.8 seconds and stopped from 60 mph in 124 feet (for comparison, that's close to a corvette).

Inside, the SRT8 uses heavily bolstered Jeep Commander seats and adds blue rings and numbers to the gauges. In addition, the speedo goes to 180 mph, aluminum highlights offer a nice sparkle, and, for a final touch, carbon-fiber trim is added to the shift lever. A new front end (with actual brake ducts) and grille are designed to add downforce to the 4800-pound sled. In back, the rearend is dominated by a centrally located pair of four-inch exhaust outlets.

The all-wheel-drive transfer case won't allow burnouts, but we like how quickly the gearbox clicks off shifts at wide open throttle. It corners nearly flat and responds so crisply SRT had to slow down the steering ratio.

On the downside, brake-pedal response is a bit too quick and brings more nose dip than you might expect. As to other trade-offs, actual payload capacity is only 750 pounds--200 less than a suzuki aerio. And with those center pipes, we'd recommend high-temp synthetic grease on your towing hardware. The missing "HEMI" badge is a Jeep thing, but we bet "trail rated" was left off on purpose.