FIA GT
In 2004, Maserati completed three MC12 GT1 race cars intended for the FIA GT GT1 class.[29] The AF Corse factory-backed squad debuted the race at Imola, yet the FIA did not allow the MC12 to score points due to its debated homologation. Even with this setback, the team managed to take second and third places. At the next round at Oschersleben, the MC12 of Andrea Bertolini and Mika Salo won for the first time. At the final round of the year at Zhuhai, the FIA finally agreed to homologate the MC12s and allow them to score points towards the championship. With this, the MC12 again took victory, allowing it to score enough points to finish 7th in the teams championship.[30][31]
In 2005, Maserati won the FIA GT Manufacturers Cup with 239 points: almost double the score of next competitor (Ferrari with 125 points).[30] The two teams that entered MC12s into the FIA GT, Vitaphone Racing and JMB Racing, finished first and second respectively in the Team Cup, with Vitaphone winning by a considerable margin.[30] Four of the MC12 drivers were in the running to win the FIA GT Drivers' Title at the Bahrain International Circuit at the start of the final race of 2005: Karl Wendlinger and Andrea Bertolini each on 71 points and Timo Scheider and Michael Bartels on 70. Gabriele Gardel of Ferrari was also on 70 points, however, and in the crucial race he placed ahead of all of the Maseratis, driving an older Ferrari 550 Maranello. Gardel took the title, leaving all of the Maserati drivers within four points of first place (Scheider and Wendlinger receiving four points for the race).[30][32]
In 2006, the only team representing Maserati was Vitaphone Racing. On September 30, 2006, Vitaphone secured the Teams' Championship for the 2006 season despite their drivers placing 5th and 7th in the Budapest 500 km race with weight penalties of 85 kilograms and 105 kilograms respectively.[33] Bertolini and Bartels also shared first place in the Drivers' Championship on 71 points but the manufacturers cup went to Aston Martin.[34]
Vitaphone Racing again won the GT1 Teams' Championship in the 2007 season on 115 points, followed by fellow MC12 team Scuderia Playteam on 63 points.[35] JMB Racing also entered two MC12s, but they were used by amateur drivers competing in the Citation Cup, which was won by JMB's driver Ben Aucott.[36] Maserati also won the Manufacturers' Cup by a significant margin while Thomas Biagi won the Drivers' Championship. Fellow Vitaphone drivers Miguel Ramos and Christian Montanari tied for sixth, while Playteam's Andrea Bertolini and Andrea Piccini were just behind.[35]
For 2008, Vitaphone Racing returned with a pair of MC12s for drivers Andrea Bertolini, Michael Bartels, and Miguel Ramos, as well as newcomer Alexandre Negrão.[37][38] The season ended with another Teams' Championship for Vitaphone Racing (122.5 points) and Drivers' Championship for Bertolini and Bartels. In the ninth round, the team fielded a third car under the name of Team Vitasystem, driven by Pedro Lamy and Matteo Bobbi which scored one point. JMB Racing retained a single MC12 for 2007 Citation Cup winner Ben Aucott and drivers Peter Kutemann and Alain Ferté, competing in the first five events of the championship.
In the 2009 season, the Vitaphone Racing won the fifth consecutive Team Championship, while Bertolini and Bartels gained their third Drivers' Championship. The other two drivers were Miguel Ramos and Alex Müller, who ended in sixth position. Starting from the fourth round, the team entered a third car under the name of Vitaphone Racing Team DHL, driven by Matteo Bobbi and Alessandro Pier Guidi, achieving good results: despite being only a one-car team, with a partial season involvement, they ended the Teams' Championship in fourth position (32 points), scoring a victory in the last round.
Italian GT
MC12s have had great success racing in Italy, and have replaced the GT3 "Maserati Trofeo Light" as Maserati's representative in the Italian GT Championship.[39] In 2005 Maserati introduced two MC12s to the GT1 division under Scuderia Playteam and Racing Box, with the teams placing first and third overall respectively.[40] The cars were re-entered in 2006, with Scuderia Playteam again securing overall victory and Racing Box coming second.[41][42][43] From 2007, GT1 cars are not permitted in the championship, and Scuderia Playteam moved to the FIA GT Championship.
Racing Box also participated in the non-championship 6 Hours of Vallelunga twice, winning in 2005 with Michele Rugolo, Leonardo Maddelena, and Davide Mastracci,
American Le Mans Series
In 2004 the Maserati MC12s were unable to compete in series backed by the ACO, such as the Le Mans Endurance Series (LMES) in Europe and the American Le Mans Series (ALMS) because they exceeded both the length and width restrictions for their class.[1] The car's nose was shortened by 7.9 in to attempt to comply with regulations, but was still 2.6 in too wide. In 2005 the governing body of the ALMS, the International Motor Sports Association (IMSA), allowed the MC12s to compete as a guest with the agreement that they were not allowed to score championship points and were forced to run a weight penalty.[16] Some ALMS teams initially objected to the participation of the MC12 due to the possibility that an accident could eliminate their chances at the 24 Hours of Le Mans, but the MC12 was finally allowed to race. The ACO stood by their ruling on the car by forbidding it from entering other Le Mans series.
The lone MC12 would be campaigned under the Maserati Corse banner, but run by the American Risi Competizione team. The 2005 American Le Mans Series season was not as successful for the team, with the team scoring no wins. In the final race at Mazda Raceway Laguna Seca, the MC12 was clipped by a competitor, causing damage that resulted in a lengthy pit stop.[48]