MAZDA'S model line has been expanded with the introduction of the Eunos 800. Billed as a highly accomplished luxury touring sedan, it joins ranks with the 30X sports coupe and the 500 executive sedan. The Eunos was introduced last year as Mazda's stand-alone premium marque and the new 800 gives the range representation in the luxury car market. A long list of standard features - such as leather upholstery, wood-grained panelling, power seats, anti-theft alarm, cruise control, high-quality stereo system with CD and hi-reflex paintwork - ensures its success in the category. Like its stablemates, the 800 is powered by a V6 engine, in this case a 2.5-litre 24-valve unit producing 170 horsepower, which is said to be exceptionally smooth and quiet. The sedan also boasts a number of interesting technical enhancements such as four-wheel steering and traction control. These features are combined with a sophisticated multi-link suspension system and ABS braking. An all-steel body, which conforms to the strict side impact regulations to be introduced in 1995 in the United States, dual airbags and seat-belt pre-tensioners make the Eunos an extremely safe car to drive. The 800's appearance is more mainstream than its more radically sculpted siblings, the ''jellybean'' 30X and the curvaceous 500. Eunos designers have attempted to create a look of distinction befitting the luxury image. The $368,000 sedan is now in the Hong Kong Eunos showroom.