DETROIT – In the next two to three years, the majority of Buicks built in North America will share common platforms and designs with Buicks assembled in China, now the brand’s most popular market.

Americans soon will see the “relevance of China,” as product sharing between the two regions grows, Buick General Manager Steve Shannon says.

“There’s a little bit now, but you will see much more significant product sharing,” he tells reporters after a speech to the Automotive Press Assn. here. “We think we can develop products jointly that really do a great job in both markets.”

General Motors Corp. and its Chinese joint venture partner Shanghai Automotive Industry Corp. share architectures for the outgoing Buick Terraza minivan, currently built in Doraville, GA, and the GL8, made in China.

Despite the platform sharing between the two regions, Shannon says there are no plans to export Chinese-built Buicks to the U.S., as the auto maker will continue to assemble and source vehicles locally.

Buick sales in China rose 24.9% to 304,230 units in 2006. By comparison, GM sold 170,064 Buicks in the U.S. last year – an 8.6% drop from year-ago, Ward’s data shows.

Shannon sees marketing cachet in Buick’s success in China, although it’s still early in the process.

“My sense is that’s an asset for marketing in the U.S.,” he says. “Other brands have found out that being hot somewhere else (is desirable).”

Shannon predicts sales in the U.S. this year will remain flat, as Buick readies the launch of its new Enclave cross/utility vehicle this summer.

The brand’s long-term future seems to hinge on Buick being a “cash cow” for GM, Shannon says, considering most Buick retailers have been teamed up with GMC and Pontiac dealerships in a combined sales channel.

Buick is taking a “brick-by-brick,” or model-by-model, approach to rebuilding the brand, instead of a wholesale portfolio replacement, similar to what GM did this year with Saturn, Shannon says.

The Enclave will replace the Rainier SUV and the Terazza, which end production later this spring, as well the Rendevous, which ceased production last month.

Assembly of the ’08 Enclave starts in April at GM’s Delta Township, MI, plant alongside the GMC Acadia and Saturn Outlook, based on GM’s new Lambda, or Global Crossover Architecture, platform.

Buick’s strength is its loyal older customer base, Shannon says, and it may have some demographic momentum given the aging U.S. population. The average age for a Buick car buyer is 67, while buyers of Buick’s truck-based models average about 54 years of age.

The sporty 7-seat Enclave, which starts at $32,740, will be a crucial test to determine whether the brand can attract younger customers in the U.S. Shannon projects buyers of the Enclave will be about four years younger than typical Buick truck customers.

“The fact that Buick makes a big, quiet, comfortable sedan isn’t that unusual a notion,” he says. “But when Enclave comes out, it will be so much unlike everything we’ve had or anybody else had. People that otherwise would be considering import luxury – that’s where we get a shot.”

Denton J. Dance, a senior director at J.D. Power & Associates on the GM account, agrees the Enclave could be the vehicle that stabilizes Buick.

“I think it will be the model that drives the brand, not the brand that drives the model,” he says.