The American Club Racing (ACR) variant of the Dodge Viper SRT-10 was first introduced in 1999 and was based on the Viper GTS. A second ACR was created based on the 2008 SRT-10 Coupé. It features much more drastic upgrades compared to the first ACR. These include street-legal racing tyres, two-piece brake rotors, adjustable suspension and a significant aerodynamic revision. The engine was not modified in any manner making it identical to the SRT-10 Coupé in terms of horsepower and torque output. A 2010 Viper SRT-10 ACR lapped the Nordschleife course of the Nürburgring with a time of 7:12.13.