with the U12 series, offered in four-door sedan and four-door hardtop body types. It was designed to have a rounded appearance in comparison to the previous generation. The hardtop sedan was later fitted with a center "B" pillar structure to increase body stiffness. The top level car was the V6 VG20ET "Bluebird Maxima" station wagon from the previous generation U11 series and was still in production at the introduction of this generation. The various grade configurations included the traditional "SSS" (SSS / twincam SSS / twincam SSS-X). In addition to the SSS series, the Bluebird wagon was replaced by the Nissan Avenir, and the sedans (LE / SE Saloon / XE Sedan / Super-select) were also available. The entry level 1600LE (five-speed manual transmission) started out at ¥1,198,000 to the top level Twin Cam Turbo 1800 cc offered on the SSS Attesa Limited (four-speed automatic) starting at ¥2,998,000 in sedan, and Hard Top bodystyles and boasted a wide variety of equipment and different combinations and grades. At the time of introduction, there was also the limited production SSS-R model, with lowered weight and a special high-power engine as well as oversized extra headlamps and racing livery. Innovations for the U12 included the introduction of Nissan's mechanical four-wheel-drive system, called ATTESA and the ever-popular SR20DET engine which was introduced in the series 2 (HNU12) bluebirds (1989–1991). With the Maxima having been spun off into its own range, U12 Bluebirds were all four-cylinder models, with either a 1.6-, 1.8-, or 2.0-liter petrol engine and also the option of the LD20 2.0-liter diesel. The sports and luxury versions came with a factory viscous LSD. Nissan made a turbocharged Bluebird from 1987 to 1990 named the RNU12, using the 1809 cc DOHC CA18DET that was sold in Japan and New Zealand. It, too used the ATTESA system. In October 1989 the U12 Bluebird was facelifted, receiving new rear lamps and other minor external changes. More importantly, the 1.8-liter engines were switched from the somewhat noisy old CA family to the new SR engines displacing 1.8 or 2.0 liters. The base 1.6 engine remained the carburetted CA16S. There was only a single 1.8, the single-point injected SR18Di with , a significant increase over the CA18i. This was also available with the ATTESA system, in either XE or SE trim. Beginning in November 1990, Nissan managed to fit an FE ATTESA trim level between the two