BERLIN -- Beijing Automotive Industry Holding Co. outlined its main reason for wanting General Motors Corp.'s European unit Adam Opel GmbH: It wants to get its hands on the U.S. auto maker's engine technologies.

Beijing Auto said in a document outlining a takeover offer that access to GM's advanced technology was the "key driver" for its bid, which is aimed at outpacing Canadian auto supplier Magna International Inc. in the race for Opel.

According to the document, GM would have to "license all alternative propulsion technologies (i.e. hybrid, fuel cells)" to Opel, including the new company's planned Chinese operations.

Beijing Auto plans to invest $2.25 billion in Opel in China to ramp up production there by 2015. It wants to expand production in China to 485,000 Opel cars by that date and plans to build a network of 400 dealerships by then, according to the document. The document is addressed to GM, dated July 2 and signed by Beijing Auto Chairman Heyi Xu.

Beijing Auto is offering €660 million ($924 million) in equity for a 51% stake in Opel, with GM retaining a 49% stake.

As part of its offer, Beijing Auto plans to establish a holding company for Opel in Germany and would require €2.64 billion in state-guaranteed loans.