I have to admit, the Shelby GT500 was somewhat of a letdown. I have no complaints about the 500 horsepower or the muscular lines, but at nearly 4,000 pounds, it's got a serious weight problem. The iron block, 5.4-liter V8 and the addition of a supercharger puts much the weight in the worst possible place -- the front -- so the GT500 feels unmotivated around the corners compared to a regular Mustang GT. Other complaints include a suspension that doesn't seem up to snuff to handle the prodigious power, as well as a vague and rubbery shifter. Despite its shortcomings, the GT500 is one of the world's best performance bargains. Never before has such a powerful car been available for so little cash (although the Ford dealers did a pretty good job of ruining its value with markups). Still, one couldn't help but think that the GT500 could have been better. Enter the GT500KR. It's the next step above the standard GT500, and the first Shelby Mustang to declare itself 'King of the Road' since 1968. A quick walk-around shows the upgrades applied at the Shelby facility in Las Vegas. Carbon fiber is used in several places, including a new heat-extracting hood, the front splitter, and on the mirror covers. The 18-inch aluminum wheels look strangely small compared to the 20-inchers on the concept, but they are handsome nonetheless, wrapped with Goodyear Eagle F1 Supercar tires. Out back is a revised spoiler lip that cleverly mimics the diffuser design below, and there's also a new exhaust system developed just for the KR. Inside, it's pretty much standard GT500, except for the plaque on the dash, KR stitching in the headrests, and a new short throw shifter with a white ball knob. Under the hood, the KR gets a new open element intake system that, along with revised programming and the new exhaust system, is good for another forty horsepower. The suspension has been modified as well. The car sits lower than before and has slightly more aggressive settings. SVT engineers claim that the GT500KR will consistently maintain 1.0g of lateral acceleration. We'll have to see about that. The keys are handed over and we're on our way. There's good news already. The new shifter that replaced the one in the standard GT500 is infinitely more satisfying. It provides clean, short shifts and moves directly into the next gear without any hesitation. That alone makes the car better to drive. Despite the firmer suspension, the KR has a pretty compliant ride and would be a suitable as a daily driver if it was asked. After getting through some traffic lights, we head up into the mountains above Salt Lake City and start getting into some curves. Once again, we're pleasantly surprised at the changes SVT and Shelby have made. The KR feels lighter on its feet than the normal GT500, even with two additional photographers stuffed in the back seat. It feels more planted and handles tight turns with far less drama. The additional horsepower doesn't seem too noticeable, although the two extra bodies, camera and video equipment in the trunk probably offset that gain. It would probably be a different story if there were only one a driver in the car. After forty-five minutes of driving the KR, we're left wondering why Ford didn't build the GT500 this way in the first place. Truthfully, it probably wouldn't have been that much more difficult. Yes, the carbon fiber hood probably wouldn't be a feasible production item from Ford (it's a company first), but the shifter, suspension tuning, and extra power would have been relatively simple. It's too bad these cars will be probably be going for around six-figures after dealer markups. And don't even think about building your own – Ford and Shelby have agreed that they won't produce any of the other parts except for replacements on existing KRs. While we loved driving the KR on public roads, Ford is giving us the opportunity to test it out on the track. Tomorrow we'll be headed to Motor Millersports Park to see how the GT500KR drives on the track. Upon arriving at the track, we discovered a sort of Mustang paradise. A host of Challenge and driving school Mustangs were joined by the full Mustang lineup, including the V6, GT, Bullitt, Shelby GT, and GT500. We were able to sample the Bullitt and Shelby GT to acquaint ourselves with the 10-turn, 2.2-mile west course of Miller Motorsports Park. After a few laps in each it was time to get into the KR. Our initial impressions of the KR on the road were further reinforced at the track. Its suspension is better balanced and makes the car feel lighter on its feet – not as much as the trimmer Shelby GT or Bullitt, but more so than the standard GT500. The chassis is predictable and is relatively easy to control even when the tires start to lose traction. That didn't happen too often, though, because of the incredible amount of grip that the KR generates. We didn't necessarily notice this on public roads, but the Goodyear Eagle F1 Supercar tires absolutely shone at the track. Their compound is unique to the KR and is close to being an R-compound. That said, they still maintain a relatively robust tire wear rating. You would think that breaking loose the tires with 540 horsepower and all that torque would be relatively easy, but not so with the KR. Much more throttle can be used coming out of apexes compared to the standard GT500, and corners can generally be taken at higher speeds. Ford claims the KR can consistently maintain 1.0g and we're inclined to believe that. The increased grip also helps to improve the KR's braking capability. The ABS has been recalibrated to work with the stickier tires and stopping distances from 60-0 mph are cut by six feet compared to the stock GT500. Each KR also comes with a functional brake duct kit that feeds cool air to the brakes via NACA-style ducts in the lower front fascia. Despite several hours of non-stop driving at the track, the 14-inch Brembo brakes had no problems with fading. The GT500KR is and will most likely remain the highest-performing Mustang ever offered by Ford. It blends the power, looks, and heritage that aficionados cherish, but now it adds a level of handling to make it the ultimate Mustang. The only downside is that so few will be made and that so few owners will experience the hard work and development Ford put into the car. With only 1,571 examples set for production throughout 2008 and 2009, a majority of KRs will most likely be purchased as investments by collectors and turn into 'King of the Garage'. Still, that doesn't take away what Ford, SVT, and Shelby have accomplished here. They could have simply added some bolt-ons, made a few cosmetic changes, slapped on the KR badges and called it a day. This is actually what we thought they did when we first saw the GT500KR at the 2007 New York Auto Show. People would still have paid thousands over MSRP just to have one if that were the case. Instead, Ford made sure that the car lives up to its name. Is the KR still the King of the Road? You bet.