Twenty years after launching U.S. production, BMW says it will expand annual capacity at its Spartanburg, South Carolina, assembly plant to 450,000 units, from 350,000, and build a new crossover at the factory.

But powertrains for U.S.-built BMWs will continue to be shipped from Germany.

“The long-rumored engine plant for Spartanburg remains just that, a rumor,” said a BMW spokesman. “Engines are the heart and soul of our company and our cars. After all, engines are our middle name — Bayerische Motoren Werke.”

IHS Automotive analyst Joe Langley says the powertrain thing is the difference between German transplants and Japanese and Korean factories in the United States. “[The Germans] are keeping the core of the brand — powertrains — homegrown in Germany and in the surrounding area in Europe,” he said. “Mercedes, too. They haven’t been so keen on building an engine facility in North America.”

At 450,000 units, Spartanburg would be the highest capacity vehicle assembly complex in the United States without an engine plant nearby.