i believe the recommended oil is castrol 5w-40 synthetic....which is sometimes hard to find.
In my Cayenne Turbo, i use Mobile 1 0w-40 synthetic....slightly less hard to find (walmart normally)
i believe both are approved oils....the reason i run M1 0-40 is because of two reasons:
1. the detergent properties of M1 0w-40 is second to none
2. the difference between 0W and 5W in terms of kinematic viscosity is almost the same at normal Connecticut temperatures.




Otherwise, pick up the oil yourself and they should deduct that from the cost of the oil change. Although, I agree with Bsick Passat and would take it to a VW dealer or specialist.