Every little detail of the road-going 164, right down to the shut line for the filler cap, is molded into the giant composite clamshells that make up the front and rear ends of the ProCar.

As proof of concept, the F1 impresario commissioned Alfa Romeo to build a prototype based on its brand-new 164 sedan. And the result was absolutely bonkers. + 11 Photos ...

But the SZ and Protèo were more different than alike under the skin. The SZ was based on the Alfa 75/Milano platform, unlike the Protèo, which borrowed the underpinnings of the brand's larger sedan.

In the interim, Alfa had switched back to rear-drive for models such as the 90 and the 75, so the front-drive 164 was still a cause for some marketplace uncertainty, especially given its size.

In both the 164 and the 164L (see "Alfa Flavors" sidebar below), this oversquare V-6 produces 183 hp at 5800 rpm. The six in the 164S, sporting a different cam profile, a less restrictive exhaust ...