You can tell the people at Jeep are pumped with self-assurance over their 2012 Jeep Grand Cherokee SRT8 – the most powerful vehicle ever to run off their production line.

And it’s not the typically gushing press release that gives their overconfidence away.

It’s the fact that when CarAdvice travelled to LA recently to take the 351kW beast for a test drive, the people at Chrysler HQ wouldn’t even tell us where we would find the car within the dozens parked off LA’s vast Sepulveda Boulevard.

They wouldn’t even say what colour it was – just that it would stand out immediately and that I couldn’t miss it.

As it turned out, they were absolutely right.

The Jeep Grand Cherokee SRT8 is every bit the monster the US 4WD brand envisioned it to be – and it’s not just the super-size 6.4-Litre Hemi V8 that lies under the bonnet, or the sledgehammer approach to styling, that gives the game away. Clearly, this is one Jeep that isn’t Trail Rated.

A quick look around the vehicle reveals a host of aggressive detailing that make this one intimidating Jeep Grand Cherokee. Take the forged 20-inch alloy wheels shod with extra-wide 295/45 series rubber on all four corners, for instance. Or the dual exhaust pipes that look to be the size of cannons.

Along with the SRT body kit there’s also a couple of serious-looking heat extractors sitting either side of the bonnet bulge and some enormous Brembo brake calipers sitting atop some equally large rotors.

SRT (Street Racing Technology) is an entirely separate division within Chrysler charged with developing high-performance versions of specific models that lie under the group umbrella.

The current SRT armoury includes the Chrysler 300C SRT8, Dodge Charger STR8, Dodge Challenger SRT8, Dodge SRT10 Viper (and Viper GTS) and, of course, the Jeep Grand Cherokee SRT8.

It’s a similar approach to the successful business models of both Mercedes-Benz with their AMG line and BMW’s M division.

The results for Chrysler have so far been encouraging, with plenty of homegrown enthusiasts willing to fork out a heavy premium for relatively low volume performance versions of their favourite models, especially the Jeep Grand Cherokee SRT8.

Sales in the United States have exceeded expectations by such numbers that Chrysler Australia has had no choice but to wind back its local launch of the vehicle by several months (Click to read news story).

That’s not to say that Australia isn’t seen as important territory for Jeep. On the contrary, so successful has the new Jeep Grand Cherokee been here that we have been allotted about one quarter of the annual 4000-unit production volume of the SRT8 variant.

With 630Nm of torque on tap and a 0-100km/h sprint time of 4.8 seconds, the Jeep Grand Cherokee SRT8 is one of the world’s fastest SUVs alongside the Porsche Cayenne Turbo, BMW X5 M and the Mercedes-Benz ML63AMG with which it shares its platform.

It’s also not short on the luxury touches. It’s a softer approach than its German rivals, which tend to be more performance focused, as in, heavier bolstered and firmer seat cushioning. Step inside the Jeep Grand Cherokee SRT8 and you’ll find plenty to like with a less aggressive treatment than the hero car styling displayed by the exterior panels.

There’s hand-stitched leather trim everywhere and it’s the soft and comfy Nappa variety that you tend to find on expensive sofas.

The entire dash and instrument panel is also wrapped in the stuff, as is the door trim. The all-hide effect is offset by a generous number of very tasteful carbonfibre accents that work well in what is otherwise a rather monochromatic theme with shades of black to differentiate the SRT8 with the standard Jeep Grand Cherokee.

There’s still plenty of bright trim work spread around here, though, especially on the superb leather-bound steering wheel, which is covered in the same Nappa hide with a flat metallic bottom and a set of paddle shifters. It’s also heated for those cold morning starts.

The deep-bolstered SRT seats are high on our list of favourite pews. Trimmed in a combination of leather with grippy suede inserts, they provide armchair comfort and sports car-like cosseting. They’re also heated and ventilated.

Hard plastics are few and far between inside this cabin and those are largely hidden below decks.

As the flagship Jeep model, the SRT8 benefits from an extensive list of creature comforts, with highlights including the voice-activated navigation system, rear park assist with screen view and audible warning, and smartbeam headlamps that react to ambient light and oncoming traffic.

But it’s the remote start that is arguably the SRT8’s show-stopping feature. It allows you to start the engine and activate various comfort settings from the key fob, while maintaining vehicle security.

On the audio front, there’s the standard-fit nine-speaker unit, but audiophiles will find it hard to resist the peerless 825-watt, 19-speaker system from Harman Kardon specifically developed for the Jeep Grand Cherokee SRT8.

Fire up the big Hemi V8 and there’s none of that expected thunder and lightening, just the sound of a smooth-running and relatively quiet engine that gives nothing away to its tarmac-blasting potential.

Heading north out of LA on the Ventura Highway provides ample opportunity to open the SRT8 up and explore all of those 630 Newton metres, of which almost all are on tap between 2800-6000rpm.

Throttle response is precise and well measured even in Auto mode, but spin the Selec-Trac rotary controller around to the Sport or Track setting and things get a lot more urgent. Overtaking slower vehicles at 130km/h becomes an effortless affair with strong in-gear acceleration. There’s also a decent exhaust note that’s worth listening to.

These performance settings dial in a sharper edge to the SRT8’s adaptive suspension, steering and transmission response, throttle, stability and traction control as well as differential behaviour.

In the standard drive mode, 65 per cent of the torque is sent to the rear axle. In Sport and Track modes those percentages of pulling power increase, while the stability control allows more slip.

Under full throttle the Jeep Grand Cherokee SRT8 makes light work of these California hills, but even in Track mode and quick-shifting with the paddles, it still behaves in a refined manner commensurate with a luxury SUV.

In this day and age of eight-speed automatics and dual-clutch transmissions, a five-speed auto doesn’t quite cut it, particularly when fuel consumption is always a concern. There’s a tendency for the Jeep to use higher revs in top gear when you’re travelling along at pace on the highways than either the ML63AMG and X5M, which gain extra cogs (7-speed and 6-speed respectively) and as a result, don’t have to work as hard as the Jeep Grand Cherokee SRT8.

Combined fuel consumption is 13.7L/100km, which compares to 11.8L/100km for the ML63 AMG, and 13.9L/100km for the X5 M, both of which are armed with more power and torque than the SRT8.

But go a little heavy with your right boot for any length of time and any benefit you might have gained from Chrysler’s cylinder-deactivation technology will be lost.

It’s a clever system and works particularly well in slow-moving traffic when only mild throttle pressure is required.

As an SRT vehicle, it’s no surprise that the ride is firm – even in the relatively sedate Auto mode.

The upside is that despite the Jeep’s size and not-inconsiderable 2300kg mass, the Grand Cherokee SRT8 handles corners remarkably well. The Bilstein shock absorbers and stiffer suspension set-up does a fine job of overcoming the SUV’s height, with minimal body roll.

There’s also the added safety net of the vehicles’ electronic roll mitigation system, which uses the electronic stability control sensors that can anticipate a potential roll then apply the brakes and modulate throttle pressure as needed.

Grip levels are high from the SRT8’s massive Pirelli Scorpion Verde All-Season run-flats tyres, and the Grand Cherokee’s full-time all-wheel-drive system provides lots of traction.

You can also feel the results of a 146 per cent increase in body stiffness over the old Grand Cherokee SRT8 – with the Jeep responding more quickly and precisely to the driver’s steering wheel commands.

The Grand Cherokee SRT8 also gets a quicker steering ratio than the standard model and there’s a satisfactory level of communication transmitted through the beautifully tactile tiller.

Braking is another area where SRT has excelled. The big six-pot Brembos up front have lots of stopping power and pedal pressure is nicely progressive.

Also helping on the safety front is an inventory of multiple safety and security features including: adaptive cruise control, anti-lock brake system with rough-road detection, brake override (when a disagreement between the brake and throttle exists and the engine power is automatically reduced so as the drive can stop the car), blind-spot monitoring, electronic roll mitigation, rain brake support (the system uses the ESC to occasionally brush the brake pads against the brake rotors to keep them dry), rear cross path (the system activates when reverse gear is engaged and alerts drivers backing out of parking spots to other vehicles approaching), trailer sway control and seven airbags.

Jeep Australia has already priced the regular Jeep Grand Cherokee highly competitively – from $45,000 – so it would be a surprise if the SRT8 version cost significantly more than its $85,990 predecessor when it arrives in August.

And when you consider that its natural rivals cost about $180,000, it’s easy to see the Grand Cherokee SRT8’s value is as powerful as its Hemi V8.