The Biturbo is the model in question, and it is important for our story for two reasons, 1) it was the first twin-turbo automobile to be mass-produced, and 2) it made landfall in America in 1984.

Some automakers have done twin-turbo four-cylinder diesels, and before you jump down my throat about it, BMW’s "Twin-Power Turbo" engines use a single twin-scroll turbocharger. Not two ...

We've already established that the first twin-turbocharged production car was the Maserati Biturbo, which debuted in 1981. The twin-turbocharger system it relied on was a parallel turbocharger system.