I have been wondering for years whether or not Porsche understates its horsepower and performance numbers. My 2008 C4S is rated at 355 hp and 295 ft. lbs. of torque. The owners manual says it will perform 0-100 k/ph or 62 mph in 4.6 seconds. With options and the additional weight of the awd system I estimate my car weighs in around 3300 lbs. give or take.
The 3.8 liter engine being a modern high technology engine should easily be able to produce 100 brake hp per liter, but Porsche shows 93.4 per liter.
With all this said, when Road and Track and Motor Trend tested my car and year model, their 0-100 k/ph times were 3.9 and 4.1 seconds. I know that there are different criteria that car companies use for rating power, JIS for Japanese cars, SAE for domestics, and DIN for German cars, but Porsche's numbers don't seem to add up.
Does anyone have any personal input or data to answer my ongoing question?

 

Almost all car companies underestimate performance figures relative to what is printed in the automotive magazines.

 

I would also add that car companies do not abuse the car to reach the indicated 0-60 numbers. The car mags rev the engine and dump the clutch. This something you don't want to do with a car you intend to keep. This also often cuts roughly a 1/2 second off of the 0-60 time.