Well you can read these reviews...Faster to 60 than a 911...yep, that sounds like a tough time to beat...if you're in the 911.
"At the track the Grand Cherokee SRT8, which rides on massive 255/45ZR20 front and 285/40ZR20 rear Goodyear Eagle RS-A run-flats, laid down some serious numbers: 5.2 seconds to 60 mph, 13.5 seconds in the quarter-mile. That makes this a 4,800-pound SUV that easily smokes a new Mustang GT, Pontiac GTO and, its most direct competitor, the Chevy TrailBlazer SS. And, you may want to sit down for this if you're a Porschephile, it's even quicker than the $90,000 Porsche Cayenne Turbo (0-60 in 5.9, quarter in 14.3)."
"Power is pegged at 420 hp at 6200 rpm and torque is an equally impressive 425 lb-ft at 4800 rpm ..."