Question: Which car, racing in the IMSA WeatherTech SportsCar Championship was first produced in 1983?

Context paragraphs:
Northeast Grand Prix: The Northeast Grand Prix (until 2006: New England Grand Prix) is a professional sports car race held at Lime Rock Park in Lakeville, Connecticut, United States as part of the IMSA WeatherTech SportsCar Championship.  Previous editions of the Grand Prix belonged to the SCCA National Sports Car Championship, the IMSA GT Championship and the American Le Mans Series.  The race currently has a duration of 2 hours and 40 minutes and takes place in July, previously having been held on Independence Day weekend compared to the Lime Rock Grand Prix that was held on Memorial Day weekend.

Grand Prix of Mosport: The Mobil 1 SportsCar Grand Prix is an annual IMSA WeatherTech SportsCar Championship race held every July or August at Canadian Tire Motorsport Park in Bowmanville, Ontario, Canada.  It was part of the every American Le Mans Series season from 1999 to 2013.  Since 1998, the race is a three-hour race, although under IMSA rules, a "three hour" race is 2 hours 45 minutes, in order to squeeze the race into a television-friendly package.  Previous editions of the Grand Prix also belonged to the World Sportscar Championship and the IMSA GT Championship.

2018 WeatherTech SportsCar Championship: The 2018 WeatherTech SportsCar Championship will be the 48th season of International Motor Sports Association (IMSA) GT Championship that traces its lineage to the 1971 IMSA GT Championship, and the fifth as the WeatherTech SportsCar Championship.  It will begin on 27 January with the 24 Hours of Daytona.

2017 WeatherTech SportsCar Championship: The 2017 WeatherTech SportsCar Championship is the 47th season of International Motor Sports Association (IMSA) GT Championship that traces its lineage to the 1971 IMSA GT Championship, and the fourth as the WeatherTech SportsCar Championship.  It began on 28 January with the 24 Hours of Daytona.

WeatherTech SportsCar Championship: The WeatherTech SportsCar Championship is a sports car racing series based in the United States and Canada and organized by the International Motor Sports Association (IMSA).  It is a result of a merger between two existing North American sports car racing series, the American Le Mans Series and Rolex Sports Car Series.  The initial United SportsCar Championship name of the series was announced on March 14, 2013, while Rolex SA signed their Tudor brand to a title sponsorship deal.  WeatherTech later signed a deal to take over title sponsorship of the series starting in 2016, rebranding the series.

Sports Car Challenge of Mid-Ohio: The Sports Car Challenge of Mid-Ohio is a sports car race held annually at the Mid-Ohio Sports Car Course.  The race began in 1963 as a part of the United States Road Racing Championship.  It was part of the IMSA GT Championship from 1972 until 1993, and the American Le Mans Series from 2001 to 2002 and again from 2004 to 2012.  From 2007 until 2012 the race took place on the same weekend as the IndyCar Series' Honda 200 and the event was sponsored by Acura from 2007 until 2009.  It was announced in July 2017 that the race would return on May 4-6 2018 as part of the IMSA WeatherTech SportsCar Championship.

BMW M6: The BMW M6 is a high-performance version of the 6 Series coupe/convertible, designed by the motorsport division of BMW.  The BMW M6 was produced from 1983–1989, 2005–2010 and 2012–present.

2016 WeatherTech SportsCar Championship: The 2016 WeatherTech SportsCar Championship was the third season of the WeatherTech SportsCar Championship organized by the International Motor Sports Association (IMSA), and the 46th season of IMSA-sanctioned GT Championship sportscar championships tracing its lineage to the 1971 IMSA Camel GT season.  It began on January 30 with the 24 Hours of Daytona.

Alexander Sims (racing driver): Alexander Sims (born 15 March 1988, in London) is a British racing driver.  He was the winner of the 2008 McLaren Autosport BRDC Award for promising young British drivers.  Sims currently drives a factory BMW M6 at the IMSA WeatherTech SportsCar Championship.  He wears an Ayrton Senna inspired helmet with yellow and a blue and a green stripe.

Oreca 07: The Oreca 07 is a Le Mans Prototype built by Oreca in 2016.  The car was built to meet the 2017 FIA and ACO regulations for 2017 for the LMP2 category in the FIA World Endurance Championship.  The vehicle also meets the regulations for the International Motor Sports Association’s (IMSA) WeatherTech SportsCar Championship for the Prototype class.  The Oreca 07 will be active in both of these Championship series as well as the LMP2 class for the European Le Mans Series in 2017.  It made its official race debut in the opening round of the 2017 WeatherTech SportsCar Championship, the 24 Hours of Daytona, and its FIA World Endurance Championship debut at the 2017 6 Hours of Silverstone.  The car is the successor to the Oreca 05.

Supporting paragraphs: Alexander Sims (racing driver) BMW M6
Answer: BMW M6