FULL MUSTANG GT500 COVERAGE @ INSIDELINE.COM: http://www.edmunds.com/insideline/do/Drives/Followup/articleId=145566?tid=edmunds.il.home.photopanel..1.* It's something like trying to drive the 2010 Ford Shelby GT500 on a roller-coaster, only there are no steel tracks to keep you from slithering off the pavement and ending up in a flaming heap of 540-horsepower Mustang. You can't even see where you're going, really. Hard on it, the GT500's rear tires begin spinning just as you can see nothing but sky in the windshield. You're on top of the hump at the entrance to Infineon Raceway's Turn 6, and as your stomach and both right-side tires go weightless, you start a long, long dive to the left, sliding sideways all the way down the hill and around the 180-degree corner. The Shelby GT500 is so torqued up with the cornering force from the low-profile 19-inch tires and the drive from the supercharged V8 that you can practically hear the welds popping in the chassis. But something is different this time - palms are not slick with sweat, tires are not threatening to let go at the most inopportune moment and steering left in order to go right is a joy and not a reflex of self-preservation. The 2010 Ford Shelby GT500 gets 2 mpg more on the EPA highway cycle this year. The Ford engineers are really proud of this. But every time we make another lap and slide down Turn 6, we have our doubts that fuel economy is what this car is about. Serving Our Inner Adolescent We're behaving like adults as the Ford engineers tell us all about the 2010 Ford Shelby GT500, even as we hear a couple of the cars making shake-down runs on the quarter-mile strip at Infineon Raceway a few hundred feet away. And in many ways, the GT500 itself is trying to act more like an adult, casting aside the muscle-bound character of the 2007 Ford Shelby GT500. As the Ford people tell us, they started with the limited-production 2008 Ford Shelby GT500KR, the exclusive (1,700 examples built) and revenue-enhancing (MSRP $79,995) Mustang produced last year. And aside from a few fewer Shelby badges (the KR had many to spare), the GT500 is like the KR in almost every way, except it's built at the Mustang plant in Flat Rock, Michigan, rather than at the Shelby facility in Las Vegas. You can tell as soon as you open the new GT500's hood, complete with hot-air extractors. The supercharged and intercooled DOHC 5.4-liter V8 with its truck-style iron block is still in place, but now it carries a conical air filter in its own sealed cold-air box behind the left-side headlight, an innovation that increases airflow while resisting power-sapping heat soak. For the GT500, this new cold-air intake required the migration of the iconic Cobra badge on the grille from the left side to the right side.