Subaru announced on May 23 that it will offer General Motors Corp.'s OnStar in-vehicle communications service, making it a standard feature next year on its top-of-the-line Outback wagons sold in the United States. Subaru will add OnStar hardware and a one-year subscription to the service on the Outback model with the 3.0 liter six-cylinder engine. OnStar allows drivers to contact a 24-hour call center at the push of a button to ask for directions, make hotel or restaurant reservations, or alert authorities in the event of an accident. New OnStar services, using voice-activation technology, allow customers to check stock prices, hear their e-mail or the latest sports reports, news and weather. OnStar has more than one million subscribers, and expects more than four million by 2003. Subaru said it will eventually expand OnStar availability to other Subaru vehicles. GM owns a 20 percent stake in Subaru's Japanese parent company Fuji Heavy Industries Ltd. . Subaru is the fourth automaker besides GM to add OnStar to its vehicles. Honda Motor Co. Ltd. and Toyota Motor Corp. both offer OnStar on a luxury vehicle. Volkswagen AG's Audi said last month it will offer OnStar on the new A4 sedan when it goes on sale this year.