By William Boston 

SANT'AGATA BOLOGNESE, Italy--Italian super-sports car maker Lamborghini is about to test the allegiance of drivers and fans with radical changes to its product line and production methods.

Automobili Lamborghini, which since 1998 has been owned by the Audi unit of Volkswagen AG, currently makes just two sports cars: the Aventador, starting at $404,195, and the Huracan, at $241,945. With its next model, the iconic brand is attempting the delicate maneuver of broadening its market while maintaining a cachet and price tag few others in the industry can match.

Its new model will be a superluxury sport-utility vehicle. Code-named "Urus" and slated for sale in 2018, it could potentially double the company's annual output to more than 5,000 vehicles.

Lamborghini, which is famous for making limited-edition versions that customers compete to own, recently broke ground on a factory for the Urus and is preparing to hire 500 employees to build the new SUV. But artisanal car-making is expensive in Italy, so for the economics to work, management is tapping the Volkswagen group for much of the vehicle's basic structure. That means it will be the first Lamborghini that is substantially not Lamborghini.

"This will radically change Lamborghini," Chief Executive Stephan Winkelmann said in an interview at the auto maker's headquarters.

Mr. Winkelmann, a 50-year-old native of Berlin who grew up in Rome and speaks English with an Italian accent, said a car giant like Volkswagen, with its multitude of models, can easily add one more design. But for Lamborghini, going from two models to three poses big risks.

"This is a major effort and you have to have a rock-solid business case and a clear idea of how to digest this," he said.

Part of that is managing customer reactions. Mr. Winkelmann knows the shift could upset many Lamborghini lovers, who value the car's exclusivity. Every single Lamborghini has been crafted by hand amid postcard-beautiful fields of grain. They are still tested on oak-lined country lanes in the area--sleek bursts of color screaming past farm vehicles and unhurried locals.

To satisfy purists, the Urus will be built at the company's home base near Bologna, where one-time tractor maker Ferruccio Lamborghini in 1963 dramatically shifted products.

The changes attending the Urus follow years of gradual acceleration for the business under Audi ownership. Since 1998, Lamborghini has boosted production more than eightfold, to 2,530 cars last year. In the past five years it has more than doubled its workforce, to roughly 1,200 employees, and recently completed a EUR400 million ($437 million) factory in Sant'Agata

Lamborghini's customers traditionally were an elite club of extremely wealthy men, mostly in Europe and the U.S. With the rise of China and other emerging economies, the market for ultra-high-end products ballooned.

Now, Lamborghini and rivals are betting that the wave of global luxury consumers is about to merge with another global trend: the shift away from sedans and hatchbacks to sport-utility vehicles.

Global SUV sales across all segments totaled 12.3 million vehicles last year, nearly double sales in 2010, according to JATO Dynamics Ltd., an automotive researcher. Its analysts say the U.S. and China now account for three of every four SUVs sold globally and that world-wide growth in the segment remains solid except in France, Russia and Turkey, which show signs of weakening.

Mr. Winkelmann and his bosses show confidence in the Urus partly because Volkswagen group pioneered high-end SUVs, first with Audi and then more extravagantly with Porsche, which is also owned by Volkswagen. Now Volkswagen's Bentley unit in England is preparing next year to roll out the first hyper-luxury SUV, the Bentyaga.

Bentley CEO Wolfgang Dürheimer understands skepticism about the new concept because he faced it at Porsche in spearheading the Cayenne SUV, which made its debut in 2002.

"When we proposed this at Porsche, no one thought it could be done," he said in an interview. Mr. Durheimer expects Bentley will repeat Porsche's success. "Our wealthy customers who want an SUV for skiing trips to Aspen will buy a Bentley."

Porsche last year sold more than 100,000 of its Cayenne and smaller Macan SUVs. Porsche and Audi share the premium SUV market with BMW AG, Daimler AG's Mercedes-Benz, Jaguar Land Rover Ltd. and car makers in the U.S. and Japan.

Prices for the overpowered vehicles haven't been announced. Mr. Winkelmann said it is premature to set a price for the Urus but expects it to be in the range of the Huracan.

While likely to be eye-popping, the lofty numbers mask a paradox of luxury SUVs: They are generally less profitable for manufacturers than their sibling top-end sedans and sports cars, due to a mix of high production costs, low volumes and pricing dynamics.

Producers of more mass-market models, including Porsche, offset that by spreading costs across greater volumes.

But volume isn't an option for ultraluxury brands, which bank on exclusivity. Lamborghini expects the Urus to double the company's total vehicle sales. But that still means producing fewer than 3,000 SUVs annually. Bentley expects to sell about 4,000 Bentyagas.

Lamborghini aims to lower its costs by using the same automotive platform on which Volkswagen group builds all its premium SUVs, including the Bentyaga, Porsche's Cayenne, Audi's Q7 and planned Q8 and even Volkswagen's Touareq. The approach is part of Volkswagen group's effort to leverage its modular manufacturing system to achieve scale even with low-volume models.

Many Urus parts will be manufactured at Volkswagen and Audi plants in Germany and Slovakia and shipped to Sant'Agata for assembly.

Acknowledging the risk of diluting the brand, Mr. Winkelmann said integration is the only way he could afford to build an SUV and contends the Urus will still be uniquely Lamborghini.

"There is no surviving for a brand like ours if you don't maintain the DNA, but this is only possible if you have a group that allows you to make synergies and scale," he said. "Otherwise, if you have to go it alone," he said, "you would have to go in big volumes," which would cheapen the brand.

It took Mr. Winkelmann more than a year to win approval from Audi and Volkswagen to build the SUV at Lamborghini headquarters. Sant'Agata competed against bids from other Volkswagen group plants that promised lower costs. Mr. Winkelmann won out with favorable terms from Italian unions and subsidies from the Italian government.

"Let's try to learn from Lamborghini," said Gian Luca Galletti, Italy's environment minister, at the recent opening in Sant'Agata of Lamborghini's new energy-efficient factory. "This shows that it is possible to attract investment to Italy."

Mr. Winkelmann said Lamborghini is considering building its first electric vehicle, a later plug-in version of the SUV.

Write to William Boston at william.boston@wsj.com

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