(Handout art / July 9, 2013)

Hoping that the best years are not in the rear-view mirror for its Acura luxury line, American Honda Motor Co. is shifting into high gear for the introduction of its redesigned 2014 MDX sport utility vehicle.

The U.S. sales arm of the Japanese automaker typically has kept a low advertising profile for Acura. But that's about to change.

This week, American Honda in Torrance plans to roll out its largest-ever national advertising campaign for an Acura model, a marketing push that also is being closely watched in the Los Angeles advertising industry.

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American Honda this year dumped Acura's longtime ad agency and called in reinforcements from Boston and New York. The two newly hired firms had to quickly add staff and engineer a campaign that would improve consumers' impressions of Acura.

"This is huge for us," said Gary Robinson, manager of Acura's national advertising and brand. "We want to get this launch right, and we are going to do what it takes to do that. This is a must-succeed."

Acura in recent years has fallen behind such high-end rivals as BMW, Lexus and Mercedes-Benz. Last year, Acura sold 156,216 vehicles, according to Autodata Corp., a 25% decline from its peak of nearly 210,000 units sold in 2005.

The Honda brand remains strong: Sales increased 9.7% in June, from a year earlier, but the Acura line suffered a 10.4% decline.

Much is riding on Acura's new "Made for Mankind" ad campaign because the seven-passenger MDX is Acura's highest-volume vehicle, and the brand's best chance to regain traction in the market.

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Last year, American Honda decided to open up its account handling more than $860 million a year in advertising spending for both the Honda and Acura lines.

The move ultimately reordered the Los Angeles advertising landscape as the incumbent firm, Rubin Postaer & Associates of Santa Monica, lost two substantial pieces of Honda's business.

Mullen, a Boston advertising firm, picked up the Acura account, and MediaVest of New York took responsibility for media buying for both Acura and Honda. RPA, which formed in 1986 to manage the American Honda account, retained the Honda creative account.

Still, the firm shed about 200 employees because of the reduction in business.

After winning the account March 18, Mullen executives had just 90 days to find office space in the Los Angeles area, hire workers and refine the advertising campaign in time to tout the MDX's arrival in dealerships.

Mullen, which now boasts nearly 750 employees nationwide, intends to eventually employ about 80 people in its newly opened office in El Segundo to work on the Acura account. The company also creates advertising for JetBlue Airways Corp., Zappos.com Inc. and Google Inc.

"This is the most exciting opportunity to come to L.A. ad agencies in the last decade," said Julie Warford, director of creative services and operations for Mullen in L.A.

The native of New Zealand joined Mullen two months ago after leaving another advertising agency in El Segundo. Mullen opened its offices next door to her old firm in 13,000 square feet of office space in a glass tower that overlooks the south runway of LAX.

MediaVest expects to add about 100 people to plan media strategy for Honda and Acura. MediaVest already had a presence in L.A., because its parent company Starcom MediaVest Group handles advertising for Disney Channel, Mattel Inc. and other companies in the area.

Acura's Robinson said the MDX advertising campaign was the largest ever for Acura, although he declined to divulge how much the company will be spending. According to advertising consultant Kantar Media, Acura spent nearly $167 million on ads in 2012, down 15% from 2011.