The Factory info states 8.75 if I remember correctly. However, I've learned that these engines do require 9.5+ quarts to fill. Why Porsche would want you to under fill your engine is beyond me...
Although I did have a customer who tried running his car with over 4 gallons of oil in it! The dipstick had broken and he just kept adding oil every couple weeks although the dash gauge read full. I had no idea that he was doing this until I went to drain the oil and it just kept coming out, and coming out, and coming out! I thought it would never stop!!