With the BPR Global GT Series reformed into the FIA GT Championship in 1997, rules regarding the cars used in the premier GT1 class were altered. Homologation specials like the Porsche 911 GT1 had already proven their worth in the final races of 1996, while newcomer Mercedes-Benz was showing the potential of their new CLK-GTR in testing. McLaren was therefore forced to give the F1 extensive modifications in order to be able to compete against cars that had been meant as race cars first and not road cars like the F1.