The Jaguar XJ Ultimate has been launched at the 2012 Beijing motor show in China - a car that could cost Australian buyers up to half a million dollars.

Jaguar XJ Ultimate - 2

The Ultimate, as the name suggests, is the most expensive version yet of Jaguar's flagship model, the XJ. The special edition luxury sedan is based on the long-wheelbase XJ and offers even higher levels of opulence and customisation options than the current range-topping XJ, the Supersport LWB.

The details that potential owners will be impressed with include the swathes of leather coating most of the interior from front to back and features individual to the special edition. A full-length leather-trimmed centre console takes pride of place between the two individually tailored power-rear seats that feature massage, heating and cooling functions and hand-finished stitching that replace the standard XJ's rear bench.

The centre console holds a machined solid-aluminium table with piano black and chrome detailing that provides rear passengers with a working area at the touch of a button. This joins the two iPad 3s and wireless keyboards housed in bespoke leather-trimmed docks in the rear of the front seats and champagne chiller with two supplied and specially commissioned champagne flutes.

Passengers are further spoiled with a new 20-speaker Meridian surround sound in-car entertainment system that includes two eight-inch high-resolution screens mounted on the back of the front seat headrests and feature wireless headphones. The Jaguar XJ Ultimate has also had its air-sprung rear suspension revised to provide optimal rear ride comfort.

The details us 'common folk' can appreciate are the XJ Ultimate's new all-aluminium supercharged 250kW/450Nm 3.0-litre V6 petrol engine's - a motor that will also feature under the bonnet of Jaguar's new hero car, the Jaguar F-Type, but with more horses. The Roots twin vortex supercharger gives the new engine enough encouragement to see the XJ Ultimate reach 100km/h in 5.7 seconds before hitting the electronic limiter at 250km/h.

The Jaguar XJ Ultimate is also available with two of Jaguar's existing powerplants: the 375kW/625Nm supercharged 5.0-litre V8 petrol engine and the efficiency-focused 202kW/600Nm 3.0-litre V6 turbo-diesel, with all setups driving the rear wheels through an eight-speed transmission. By 2013 the new supercharged aluminium 3.0-litre will wholly replace Jaguar's ageing 283kW/515Nm naturally aspirated 5.0-litre V8.

While the Jaguar XJ Ultimate impresses its occupants inside, the subtle exterior won't be drawing too much attention. Chrome sculpted lower air intakes match the classic Jaguar grille while polished stainless steel oval exhaust tips, LED daytime-running lights, 20-inch Maroa forged 'dual-surface' alloy wheels and subtle 'Ultimate' badging are the only hints of the car’s limited nature.

The first 20 XJ Ultimates will only be available in Celestial Black but Jaguar says for XJ Ultimates produced after these, customers can order their car in Polaris White (pictured) or any shade of their choosing. Adding further to the car's potential for exclusivity are the three interior colour choices for the seas of leather and customer-specified headrest embroidery, providing buyers with a truly bespoke experience.

Jaguar Australia brand manager Kevin Goult says the XJ Ultimate will be available and sold in Australia with the model available for build from October 2012, adding, "a customer would be able to order one now through the showroom if they so wished."

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