Open Single Seater), designed to encourage a wide variety of open wheel racing cars. Production Touring Cars was a variation of the cars eligible for Australian Production Car Championship, although there was an emphasis placed on cars with as few modifications as possible from road specification, something which the APCC no longer represented. 3.3 litre Holdens was a Victorian-based variation of the popular entry level HQ Holden category. Unlike HQ Holdens where only the HQ model of Holden Kingswood was permitted, later models HJ, HX and HZ were also permitted. Classic Touring Cars was more or less a direct copy of Group N Historic Touring cars. Super Tin Tops was a touring car type of category intended for slower and less modified cars than those in the Touring Car Challenge, the obvious targets were competitors in Improved Production and Sports Sedans and more limited categories like Saloon Cars and Commodore Cup. Controversially, Stockcar Thunder Road was included, intending to provide the once popular Australian NASCAR competitors a category to race in, however after much hype and promotion no competitors emerged. Continued growth The pre-existing categories grew promisingly with Touring Car Challenge and Thundersports well supported. Production Touring developed its own group of competitors. OzBoss was slow to take off and was quickly merged into Formula 4000 grids. Similarly Super Tin Tops was slow to gather momentum and some Production Sports Car type vehicles were included and Classic Touring Cars were merged as well. Despite this the series 2006 series ended promisingly and most categories continued to grow into the 2007 season. The Inter Marque Championship for production sports cars was a successful addition to the series, bringing large fields. Another addition was the X Challenge series, providing a destination for competitors in the collapsed Lotus Trophy series, a one make series for racers of Lotus Exige and Lotus Elise cars. 2008 season and legacy The series was retagged as the Australian Motor Racing Championships for the 2008 season. However the new season has seen entries drop across the board, a near nationwide trend but the AMRC has been hit harder than the average. Formula Holden has dwindled to less than a handful of cars and OzBoss, which grew promisingly in 2007 has dwindled also. Thundersports became only contested by the former Future Racers. The faster Sports Prototpyes, typified by the West WR1100 cars have been pushed aside into a new