Only a few hours after we posted the first brochure shots of the all-new Sai and Toyota officially took the veils off its new hybrid sedan that will make its public outing at this week’s Tokyo International Motor Show. Larger and more luxurious than the Prius, the Japanese automaker’s second dedicated hybrid car is a sister model to the Lexus HS 250h that recently went on sale in the U.S.

In fact, the two vehicles differ only slightly in appearance with the Sai featuring a new front end design with a unique treatment for the head lamps, bonnet, grille and bumper and different tail lights (even the rear bumper remains the same) and alloy wheel designs.

The reshaped rear side windows and the absence of protective / decorative door trims sum up the exterior revisions over the Lexus HS 250h.

Toyota’s designers spent a few more hours -metaphorically speaking- on the Sai’s interior as the hybrid model features a new instrument panel and center console design as well as a different steering wheel and less fancy trim than its Lexus counterpart.

There are no hidden surprises under the hood as the Sai features the same gasoline-electric hybrid system as the HS 250h. In other words it’s powered by a 2.4-liter Atkinson-cycle VVTi four-cylinder teamed up with an electric motor and a battery pack to achieve a total system output of 190 horsepower. A continuously variable transmission and front-wheel drive round out the drivetrain.

The new Toyota Sai hybrid sedan is planned to go on sale in Japan on December 7, 2009 with a monthly sales target of 3,000 units.

It will be offered in four trim levels with prices ranging from 3,380,000 yen to 4,260,000 yen ($37,200 to $46,800 US at today’s exchange rates). In comparison, the HS 250h is priced in Japan between 3,950,000 and 5,350,000 yen ($43,500 to $58,800). Toyota said it that

Toyota did not say whether the Sai will be available in other markets outside Japan.