NEW YORK -- Stop me if you've heard this one before: There's this famous car brand whose average driver is more familiar with Social Security than social media.General Motors will make another attempt to get Buick to appeal to younger buyers with fresher versions of the Regal midsize sports sedan and the LaCrosse large luxury car. GM unveiled the pair Tuesday ahead of the New York auto show.Youth has been the theme of several of Buick marketing campaigns during the last three decades, with famous pitchmen from Tiger Woods to Shaquille O'Neal. Sales have even risen recently after a dramatic and lengthy decline. But even with that recent success, odds are against GM making Buick a go-to option for large numbers of drivers below age 40.Buick, once coveted for its understated elegance, used to be a dominant brand. In 1984, GM sold 942,000 Buicks in the U.S., according to Ward's AutoInfoBank. But many Buick buyers died, and younger people opted for SUVs and cooler European cars. Sales bottomed out at just over 102,000 in 2009. GM only kept the brand alive because it became a huge seller in China.Buick sales rose the past three years, hitting 180,000 in 2012. The brand might never approach its previous high, but GM says it can still make money selling the higher-priced luxury vehicles.Driving sales are the new Verano, a compact based on the Chevrolet Cruze, and the Enclave, a big crossover SUV that got a facelift last year. Buick's new Encore small SUV is just starting to hit showrooms.GM is giving the LaCrosse a more sculpted, modern look. It gets updated LED daytime running lamps and tail lights and a larger front grille. On the inside, it gets new, more supportive seats and a modernized center stack with fewer buttons than the current car. The interior will have more of a luxury feeling to differentiate it from the sportier Regal.The Regal also will be updated, but details weren't yet available. The New York International Auto Show opens to the media today.The LaCrosse goes on sale late this summer, the Regal in the fall. Prices and gas mileage weren't released. The current Regal starts at $29,015, while the LaCrosse starts at $31,660. Buick's new products have changed its demographics. In 2006, Buick buyers' average age was 66. Last year that fell to 57, according to the company.But Buick buyers are still older, and the automaker would like to catch more people in their 40s. The average new car buyer in the U.S. is 52, according to the TrueCar.com auto pricing site.And Buick hasn't kept up with the industry. Last year, sales grew only 1.6 percent as total U.S. new vehicle sales rose 13 percent.Spokesman Nick Richards blames the slow growth on a cut in low-profit fleet sales. He says retail sales to consumers rose about 6 percent.Buick was outsold last year by some popular midsize cars, like Ford's Fusion with 241,000 sold. But the brand did outsell some competing luxury brands, including Acura, Infiniti and Lincoln."The vehicles themselves are very suited for young driving habits. Good fuel economy, performance, nice looking," said Rebecca Lindland, owner of Rebel Three Consulting of Greenwich, Conn. "But it's still not cool to be in a bar and say you have a Buick."