Group A racing consists of production automobiles that have a minimum annual output of 5,000 units. The governing regulations are very restrictive to any engine and chassis modifications, so the races are done with close to stock cars. For this reason Group A racing is an ideal outlet for major automobile manufacturers to show their car performance. In May 1989, the Nissan firm of Japan completely changed their Skyline stable, and also brought back the renowned "GT-R" after a 16 years absence. This new generation GT-R was, just like its predecessor, created as a road-going racer designed for competition. The powerful 2568cc, DOHC six cylinder power plant features twin turbochargers that gives the stock engine 280 horsepower. When race-tuned, it is said to have an awesome 600 HP output. In order to harness this increased power, the GT-R uses Nissan's ATESSA ETS torque splitting 4WD train, plus a SUPER-HICAS four-wheel steering system. In 1990 two Skyline GT-R's from the Nissan works racing team, entered the Japanese Group-A Touring Car Championships, and monopolised the season, taking all six victories. Observing its phenomenal performance, many of the other teams chose the GT-R from the next season. 1993, one team was sponsored by HKS (a Japanese tune-up parts manufacturer). The HKS Skyline GT-R became quite popular with motorsports buffs, due to its colourful body scheme and racing potential.