<< The only thing that could even compete was the Panamera Turbo. The RS7 comes with an even more powerful version of the familiar 4.0-liter twin-turbo V-8 -- 560 horsepower to be exact. For 2014, Porsche's seemingly underrated 4.8-liter twin-turbo V-8 is up 20 hp to a more-than-modest 520 hp. Faced with tough choices after the two hit the test track and a canyon road, Jonny enlists the help of resident Motor Trend Hot Shoe Randy Pobst to figure out which super sedan is best. Website - http://www.motortrend.com