With the Panamera S said to be dropping the naturally aspirated V8 and gaining a twin turbo V6 offering a 20 horse bump as well as torque gains the Panamera Turbo will likely need to receive a bump as well. Porsche specifically testing the Turbo model here leads PorscheBoost to believe they will respond to increased competition from Audi and Mercedes. BMW seems content to leave the M5 and M6 Gran Coupe as they are.
A 20 horsepower bump for the Turbo models seems within reason. The turbo going to 520 horsepower and the Turbo S to 570. Similar to the gains the S models will see. Time will tell, enjoy the video below. Expect this facelifted model to be revealed later this year as a 2014: