The championship-leading Corvette DPs have been pegged back with weight and restrictor adjustments ahead of next weekend’s Continental Tire Road Race Showcase at Road America.
Balance of Performance changes, meanwhile, have also been made in the GT Le Mans category for the ninth round of the TUDOR United SportsCar Championship.
After having claimed six out of seven wins this season to date, the Corvette DPs will head to Wisconsin with a 10 kg minimum weight increase and 0.3 mm smaller air restrictor.
The GTLM class sees changes to the Ferrari F458 Italia and Porsche 911 RSR, with both cars losing 10 kg of minimum weight.
The Prancing Horse will receive a taller rear wing, while the gurney height of the Porsche has been reduced.
The BoP changes, which go into immediate effect, are the first since last month’s round at Watkins Glen.