Depends how much and how you drive the car. If you want to get real specific send a sample of your oil off to be analyzed.
Personally I do one oil change a year on the cobra, but I drive less than 2k a year on that car
"I'm not driving too fast...just flying too low"
-03 SB Cobra vert- 2552 of 5082 Born 02/25/03
90 7up vert - new project-07 DSG Focus -DD