Top 10 Most Powerful Sedans

7. BMW M5 / M6 Gran Coupe - 560 HP

Both the BMW M5 and M6 Gran Coupe share the same powerplant: a 4.4-liter V8 twin turbo with 560 hp and 502 lb-ft of torque. The M6 Gran Coupe however, accelerates to 60 mph 0.2 seconds faster than the M5 (4.3 vs 4.1). The M5 is cheaper, with a starting price of $93,825 while the M6 Gran Coupe starts from $115,925. Fuel economy favors the M5 sedan with a 15 mpg city, 22 mpg rating while the M6 Gran Coupe is rated at 14 mpg in the city and 20 mpg on the highway.