The A80 program began in February 1989 under various teams for design, product planning, and engineering led by Isao Tsuzuki. By the middle of 1990, a final A80 design concept from Toyota Technical Centre Aichi was approved and frozen for production in late 1990. The first test mules were hand-built in A70 bodies during late 1990, followed by the first A80 prototypes being hand-assembled in 1991. Again using subframe, suspension, and drivetrain assemblies from the Z30 Soarer (Lexus SC300/400), pre-production of the test models started in December 1992 with 20 units made, and official mass production began in April 1993. The fourth generation of the Supra again shared its platform with the upscale Soarer coupé, sold in the U.S. as the Lexus SC. Although the two cars looked similar dimension wise, the new Supra was more than 13 inches (340 mm) shorter than its luxurious cousin.