The world's newest cars are on display at the Shanghai auto show, but Xu Xingen came for a classic that is perhaps equated with success and power in China more than any other -- the Audi A6.

Half of the Audi A6s in the world are sold in China, according to research firm Dunne & Co., where black versions with windows tinted darker than welding glass are the car of choice for government officials and company bosses.

"Many Chinese people like the Audi car a lot," Xu said, after testing the back seat, where the 50-year-old entrepreneur plans to ride most of the time. "It looks very beautiful, magnificent. I am going to buy a black one."

Boosted by A6 sales, Audi posted a record first quarter in China with sales up 18.2 percent and 51,951 cars sold. CEO Rupert Stadler said at the Shanghai auto show that China was set to become Audi's largest market this year.

"In China, Audi is considered to be officials' favourite car," another 50-something Chinese executive said after his office manager snapped a photo of him behind the wheel of the A6.

"The streamlining, the design, the space are all very good so Chinese officials started to drive this car very early. I am going to buy one," he said. He declined to give his name, but said he was "from a Fortune 500 company".

The Audi stand's A6 was silver, but he said that would not do: "Black looks more mature and sedate. Usually officials all drive black cars."

The car's status is such that in Beijing, the importance of government meetings can sometimes be gauged by counting how many A6s are parked outside.

Whistleblower Lu Jianfu, who has gained a following on China's Internet by using his video camera to catch government officials abusing their authority, credits a black Audi with launching a hobby that has led to at least 10 officials being fired or punished.

In 2007, Lu saw an Audi sporting a flashing police light, driving against traffic on a one-way street. When police told the driver to back up, he said the car "didn't have a reverse gear", Lu told the China Daily.

Lu shot a video of the scene and posted it online. The Audi driver, an official for the central city of Zhengzhou, was sacked as a result.

A newspaper reporter in the northern city of Xian borrowed an Audi A6 last year to test theories circulating on the Internet that by just sitting in an A6, women would spontaneously ask you for rides.

His conclusion: the claims were a myth.

The A6's status comes down to Audi being one of the first premium manufacturers to enter China, said Klaus Paur, head of Synovate Motoresearch for Greater China and Korea.

Initially, it was a popular government car, but then entrepreneurs started buying them too.

"A lot of people bought these A6s simply because it was, socially speaking, acceptable," Paur said. "People would not say 'you are showing off' because it was also endorsed by the government."

But Audi A6s run the risk of becoming too common in China and losing their luxury status, compared to rival brands like BMW, Paur said. As a result, the company is trying to promote cars like its new Q3 compact sports utility vehicle.

Audi's CEO is confident the brand can become even more ubiquitous.

"It took us 23 years to sell our first million vehicles in China," Stadler said. "We aim to deliver our second million customers in just three years."