The extra power isn’t life changing. Subjectively, the Cayman S PDK we drove (Porsche didn’t let us drive any other setup) felt about as quick as the 2008 model. Porsche claims a PDK-equipped Cayman S will accelerate to 62 mph in 4.9 seconds when performing a start in sport plus mode with launch control, a feature only available with the optional Sport Chrono package. We’d call that an extremely conservative estimate, considering the 4.8-second sprints we’ve whipped out of a 295-horse, manual-transmission S model and that launch-control starts are engineered to allow the car to accelerate as quickly as physics will allow. We’ll have to wait to test both transmissions to see which is ultimately quicker, but for now our money is on the PDK, with the manual a 10th or two behind.
Source: Car and Driver