25. Alfa Romeo Giulia Quadrifoglio
What do you get when you take a Ferrari V8 engine, chop two cylinders off and cover it with a gorgeous Alfa Romeo body? You get the infamous Giulia Quadrifoglio. This car is one of the fastest four-door sedans you can own thanks to a 2.9-liter twin-turbo V6 with 510 HP on tap.
Although it is not an Alfa engine per se, it is still from a company historically connected to Alfa. And that is good enough.