The manual says GF-4. All GF-4 oils are full synthetic. The reason is because of the immense heat at the turbo shaft bearing that destroys non-synthetic oil and causes turbo shaft bearing failure. Mobil 1 and other full synthetic oils can stand up to that torture for 6,000 miles without breakdown. Mobil 1 is GF-5 oil and exceeds GF-4 specs. Any GF-4 or GF-5 oil is what you want.