The mesh grille of the Denali...
The mesh grille of the Denali makes the truck stand out from its lesser Sierra siblings.
When I climbed into the '07 GMC Sierra Denali, I'll admit, I had one thing on my mind-the 6.2L V-8 and the 400 hp that came with it. Okay, so it has 403 hp, but it crossed the 400hp threshold, and that's what I was looking forward to. After a week behind the wheel, and after getting back into our long-term '07 Silverado LTZ loaner, the 6.2L and six-speed 6L80E transmission were what I missed most. Yes, the Silverado's 315hp 5.3L does a good job of moving a Crew Cab truck around-when coupled with the four-speed 4L60E transmission-but the added power and gears from the Sierra made driving the GMC much more enjoyable. The highway-friendly 3.43 rearend was countered by the 6L80E's low 4.02 First gear, to get the Denali up to speed in a hurry, and the close-shifting from Second through Sixth, which ensured the engine would stay at a happy rpm without lugging down between shifts.
The 6.2L Denali consumes considerably more fuel. Our Denali showed less than 400 miles on the odometer when we began driving it, and the combination of its fresh-off-the-lot engine and my eager right foot wreaked havoc on the fuel economy. According to the truck's electronic display, our overall average was less than 15 mpg. This stood below the combined average of the city and highway EPA estimates of 13 and 19 mpg.
Inside of the Denali is a more luxurious version of what you'd find inside of a Silverado LTZ, however, with the same navigation and rear-seat entertainment. As we've come to expect from the GMT900 interiors, everything was well put together. Our only complaint being the rear-seat window switches were not quite flush with the armrests. The switches fitted as they were designed, but rear-seat passengers would often startle themselves by inadvertently opening windows when they bumped the switches. Besides that, the interior was quiet during cruising speeds and acceleration; which was almost disappointing considering how nice the 6.2L V-8 sounded. I expected the ride from the optional 20-inch wheels to be a bit harsh, but it managed to be a great compromise between firm and compliant.
Obviously, the two interpretations of the '07 GMT-900 truck platform have distinguished themselves on the outside more than previous generations have, with the Silverado and Sierra getting different beds and taillights, in addition to the unique front sheetmetal and grilles. The Denali takes the look a bit further, with chrome 20-inch wheels and a bold grille that's perforated with circular holes. The appearance upgrades take the Sierra up market without too much flash, but its subtle differences are enough to garnish extra attention from truck enthusiasts.