All the Ferrari F430 GTs at Le Mans have been obliged to fit carbon-fibre gurney flaps to their front and rear wheel-arches following a rules clarification issued on Tuesday.
"It may give us a little bit more drag," Rick Mayer, Risi Competizione technical director told AUTOSPORT. "We'll set up something better for the race but they [the ACO] won't let us run in the qualifying sessions unless we do something.
"It's just an inconvenience - we're running the same car that won the class last year and it's been legal all this year."
It is understood that the Risi cars passed scrutineering on Monday, but all the Ferrari teams were informed on Tuesday that new bodywork had to be fitted in order to comply with a rule stipulating that the tyre must not be visible above the centre-line of the wheel when viewed from the rear.
"Michelotto had to run off these carbon-fibre gurney flaps for everybody in a hurry," said Mayer. "I thought it would be a homologation thing but apparently it's not, so we're going to make our own parts."