In 1970 Porsche gave the controversial 914 a unique and rare racing package upgrade. The M471, as it was called, was built for homologation in SCCA racing. The car had the same flat-six motor as the standard 914/6 but was outfitted with steel fender flares and front valance, a fiberglass rocker panel, and larger wheels. Only 23 of these factory-built race cars were made available to the public. Today these are known to be some of the most collectible Porsches, the last of which was built in 1972.