Last year, the EPA made clarifications to existing rules prohibiting owners, operators, aftermarket companies, and service businesses from tampering with or removing emissions equipment on EPA-certified vehicles, causing a small uproar in the car-modding and amateur racing communities. But the clarifications weren’t enough to un-muddy the legal waters of vehicle modifying, as a comment from Moreland demonstrates. "For more than two decades, we have sold this product under an accepted regulatory approach that permitted the sale of competition-only parts,” he said. “In our view, it is and was legal to use in race conditions in the US.”