Toyota Mark X late 1960s. Instead of being based on a modified Supra chassis "A" series platform, the Mark X continues to use the Toyota "X" platform, and does not share its platform with the Toyota "S" series platform used under the Toyota Crown and the Lexus GS. The continuation of describing this vehicle as the "X" series is a reference to the first dedicated Mark II platform introduced in 1972. Major changes to the Mark series are the engine and footwork. Toyota discontinued the straight-six engines used in the Toyota Verossa, which included the JZ series and the G series engines, and
Toyota Aurion (XV40) Toyota Australia then commenced work on the development of the car, concurrently developing both the Australian car and the version for Asia. Beranger proclaims that the entire engineering undertaking, "is probably one of the most significant jobs that any subsidiary of Toyota Japan has done anywhere in the world." The Australian variant of the car was codenamed "323L". Despite both cars being essentially identical, Australia was given a different code due to the car occupying a broader range in that market—from a fleet vehicle to a sports-oriented model. In Asia, the car's role is much narrower, being a high-end luxury