The E39 BMW M5 is often credited with starting the German horsepower wars. In 1998, it was the fastest four-door sedan in the world, producing 394 hp from its 4.9-liter V8. Few people would have guessed that in just a few years, this would be the baseline for sporty sedans, and tuners would be producing cars with close to twice that figure. And that the 2025 BMW M5 would pack 717 hp.
Â
