Toyota Motor Sales USA Inc. is partnering with i2 Technologies Inc. to develop iStarXchange, an online marketplace for the $100 billion U.S. auto parts, service, and repair industry. Toyota Motor, the U.S. sales unit of Japan's Toyota Motor Corp., the world's fourth-largest automaker, said iStarXchange will operate as an independent entity and be based in Torrance, Calif. The virtual marketplace will help make sales more efficient for the estimated 160,000 buyers and 66,000 sellers in the American automotive replacement-part market, Toyota said. Dallas-based i2, a software provider for electronic business, will provide the implementation and support, as well as host and manage the marketplace. Equity shares in iStarXchange will be divided between Toyota and i2, with Toyota Motor Sales holding a majority stake.