In 1975, BMW introduced the 3 series, a sporty sedan that became synonymous with the brand's performance image.
Forty years later, despite intensifying competition and changing customer tastes, the 3 series still dominates its segment. Competitors openly benchmark the 3 series and target it in their advertising. Buff books lavish it with praise. Dealers love the repeat business.
In many ways, the 3 series is BMW, the brand with the enviable mystique built on German engineering and uncompromised performance.
But the competition is coming on strong; some experts say the Mercedes-Benz C class and Cadillac ATS are already on par with the 3 series when it comes to technology and performance. The next-generation Audi A4 due next year could be another tough rival.
The question is whether BMW can maintain the 3 series' performance aura in a market demanding more luxury, connectivity, semiautonomous driving technology and increased fuel economy.
BMW can't afford not to.
The 3 series accounts for about 25 percent of BMW sales worldwide, the automaker says. In the United States, 501,569 luxury compact cars were sold last year, and the 3 series (and its spinoff 4 series) accounted for nearly 28 percent of those sales -- a percentage BMW has maintained seven out of the last 10 years.
Dealers testify to the nameplate's market strength.
"I've had repeat buyers over and over again. Over the years, the 3 series has evolved, and the technology has evolved, but they have not rested on their laurels," says Joe Laham, owner of BMW of Cape Cod in Massachusetts.
Laham, who sells 10 other brands including Audi and Volvo, says rivals have a hard time conquesting 3-series buyers.
"Everybody has tried to benchmark it," he says. "I do value my partners, but it is tough to compete with the legend."