The Subaru Alcyone SVX made its debut, as a concept car, at the 1989 Tokyo Auto Show. Italian automobile designer Giorgetto Giugiaro of ItalDesign designed the slippery, sleek bodywork, incorporating design themes from is other concepts, such as the Ford Maya and the Oldsmobile Inca. Subaru decided to put the concept vehicle into production and retain its most distinguishing design element, the unconventional window-within-a-window. Subaru called this an "aircraft-inspired glass-to-glass canopy," which was adapted from the previous model Subaru Alcyone with an additional extension of glass covering the A-pillar. The decision to release this car for production gave the public the first opportunity to buy a "concept car" as conceived. The suffix "SVX" is an acronym for "Subaru Vehicle X".
In contrast to the boxy, angular XT, the SVX had curvy lines designed by Giugiaro and the unusual two-piece power side windows. The windows are split about two-thirds of the way from the bottom, with the division being parallel to the upper curve of the door frame. These half-windows are generally seen on exotic vehicles with "scissor", "gull-wing", or "butterfly" doors, such as the Lamborghini Countach, De Lorean DMC-12 (another Giugiaro design), and the McLaren F1. The SVX's aerodynamic shape allowed it to maintain the low drag coefficient of Cd=0.29, previously established by the XT coupe it replaced.
Unlike the previous model, which had been available with either a turbocharged flat-four (as XT) or a naturally aspirated flat-six (as XT6), the SVX debuted with and remained available with only one engine, the EG33 model 3.3-liter boxer horizontally opposed flat-six. This engine was the largest engine produced by Subaru for its passenger cars until the introduction of the 3.6-liter EZ36 engine in the 2008 Subaru Tribeca. The previous generation Subaru Alcyone had installed a turbocharger on the four cylinder engine, but the larger EG33 was more powerful and a turbo was not installed. The new 3.3-liter variant was equipped with dual overhead camshafts and four valves per cylinder, and had an increased compression ratio of 10.1:1, bringing horsepower up to 231 hp at 5,400 rpm with 228 lb·ft of torque at 4,400 rpm.