(FORTUNE Magazine) – First it was French impressionists. Now it's classic cars. A group of Japanese businessmen recently paid a record $15 million for a 1931 Bugatti Royale sold by a London car dealer. Now Christie's is hoping to get at least $12 million for a 1957 Ferrari 315S. Says Colin Crabbe, director of what the auction house calls its motor-car department: ''You have to think of it as a work of art.'' To let prospective Japanese buyers see the machine in all its glory, Christie's air-freighted it to Tokyo and displayed it at a caviar reception as part of a tour that also took in Hong Kong, New York, Paris, and London. Then back to Monte Carlo, where the car goes on the block with 40 other classics. Citicorp's private banking group, which handles the needs of wealthy clients, including art collectors, co-hosted the Tokyo affair. Explains a bank exec: ''We hope for cross-fertilization.'' Many collectors like to drive their finds and open up the throttle. Since Japan's crowded roads make this tough, some speed around a racecourse at the foot of Mount Fuji. A few keep their autos overseas and take fly-and-drive vacations to such places as California and France.