"Look Ma, No Engine..."

Nissan, Porsche, Bentley, Volvo, Audi, Lamborghini, Mazda, GM, Volkswagen all racing without engines.
"The cost of building these racers is impossible to calculate because so much time, labor and material was donated or sponsored. Still, if you were to factor in all the R&D, the most exotic of the bunch would cost upward of $100,000 to replicate. As for the countless hours that designers and engineers are devoting gratis: priceless."