Herding bulls through the Rocky Mountains in the Giro Lamborghini

The airy mountain passes of Colorado are behind me, the howl of engines fading, and suddenly it hits me -- I'm still wearing the wristband.

The rubber bracelet resembles a rock concert souvenir, but it would take a Beatles reunion to match this high-decibel show: The 2012 Giro Lamborghini, an annual road tour of Lamborghini owners that included my first drive of the Aventador. This 217-mph, 691-hp, $394,000 Italian bull wields the sharpest horns in the brand's nearly half-century history.

The warm-up act wasn't bad, either. The Gallardo LP-570 Super Trofeo Stradale is the bantamweight, hardcore version of the V-10 sports car that — with financial and technical backing from corporate sugar daddy Audi -- dragged Lamborghini into the modern age of more reliable, everyday-drivable machines. At least for fortunate folks who can afford the Trofeo's $261,000 base price; and can nab one of roughly 30 copies bound for the States, from a limited worldwide run of just 150 cars.

In a three-day convoy of 29 Lamborghinis that torched roads and blew minds from Telluride to Denver, the Aventador blended in and stood out, depending on its mood. Born to its lead role in Lamborghini's exhibitionist family, the Aventador is the diva you'd expect at these ticket prices, with a rafter-shaking, 6.5-liter V-12 and the world-straddling looks of a James Cameron movie fantasy. And when I dutifully trailed a line of older Murcielagos, now succeeded by the Aventador, I noticed how well the brand's exotic cars tend to age, how smoothly they hand off to the next generation -- and how little credit Lamborghini gets for that fact. It's not easy to keep spaceships looking fresh, or to keep them from appearing dated.

Yet the Murcielago's wrinkles and sags were showing, and the Aventador fixes most of them — tummy tuck aside. This is one vast, lane-sucking sports car, an inch wider than a Chevy Suburban, and weighing closer to 4,000 pounds than its listed curb weight of 3,450.

That husky overall weight comes despite the Aventador's lightweight, carbon-fiber structure: A first for Lamborghini, combined with a nifty front suspension design that replaces bulky coil-over shock absorbers with a slim, elegant aluminum pushrod.

That carbon-fiber diet can also be found in the less costly, $225,000 McLaren MP4-12C. Yet the Aventador's brazen style — with enough planes and geometry to give Euclid a mental workout -- makes the McLaren seem generic and almost neutered in comparison.

The X-fighter theme continues in the beautifully rendered cabin, dominated by a sleek banked console that suggests lift-off capability. In modern supercar vogue, a bright, legible digital display greets the driver, with a 9,000-rpm tachometer and animated readouts for each of seven available gears. To start the V-12 Armageddon, just flip open a red metal cap to reveal the start button.

Where the Murcielago, like a high-maintenance partner, forced you to make all the compromises, the Aventador meets you halfway. As in the Gallardo, the Aventador incorporates Audi's intuitive MMI control knob and its screen for navigation, entertainment and vehicle functions. Lamborghini purists once sniffed at the presence of common Audi interfaces in their bespoke machine. But a slick, contemporary Audi system beats a road map and an Italian AM/FM radio, and complaints quickly dried up.

With apologies to its faithful, limber owners on this trip, the Murcielago's unyielding seats, off-center steering wheel and elbows-locked driving position always felt like being waterboarded. And while the Murcielago made real performance strides over its career, its stony, unapproachable nature made my life-in-danger radar flash much too soon.

But when I squeezed past the Aventador's crowd-pleasing scissor doors, its relatively natural driving position, along with more-sensitive steering, made it easier to get comfortable, crank up the pace and focus on the road ahead.