In Japan, the equivalent Toyota Aristo, which debuted in 1991, was sold until the introduction of the Lexus marque and the third generation GS in 2005. Following the debut of the third generation GS in Japan, the Aristo was discontinued. Though largely identical in exterior and interior design, first two generations of the GS and the Aristo differed in their engine and transmission combinations as well as equipment packages. Competitors to the Lexus GS include the BMW 5-Series and the Mercedes-Benz E-Class.
With a body styled by the famous Italdesign Giugiaro firm, the Aristo was launched in October 1991, offering two inline-6 powered versions for the Japanese market: the 3.0Q and 3.0V. The 3.0Q Aristo featured a 2JZ-GE engine which produced 226hp (169kW). The 3.0V Aristo was equipped with a 24-valve twin-turbo 2JZ-GTE engine which produced 276hp (205kW). This twin-turbo engine was the same as could be found in the Toyota Supra Mk IV (JZA80). In 1992, a third model, the V8-powered 4.0Zi-Four (codename UZS143), joined the Aristo lineup. This model came with standard four-wheel drive and a 250 hp (186 kW) 1UZ-FE engine. This V8 had also been used in the first generation Lexus LS and the Toyota Crown Majesta. The Aristo/GS models were equipped with an independent, double-wishbone suspension setup. The only engine available for the export markets was the 2JZ-GE inline-6.
Production of the Lexus GS 300 (JZS147) began on February 22, 1993 at the Tahara, Japan assembly plant. At the time, the GS represented the latest advancement of Tahara production technology, with only eight spot welds performed by hand. The rest, some 4,200 welds, were performed by robots. Italdesign Giugiaro's exterior styling blended elements of the original LS flagship and SC performance coupe in a rounded, aerodynamic shape, complementing the rest of the Lexus lineup. The vehicle adopted a wedge-like shape with high rear decklid, and longer and wider proportions than competing vehicles. The exterior shape of the original GS produced a drag coefficient of Cd 0.31. Offered color schemes included single-tone bumper and body finishes, along with dual-tone schemes.