I read through the tech question and answer and cought something interesting. One person wrote about changing the oil himself between the 15,000 mile dealer serivces and so on..... The tech wrote that when changing the oil yourself, you should use the same exact brand that the dealership uses which would be a Castrol brand. He stated that using any high quality synthetic oil is fine but it's the CONSISTANCY in using the same brand that matters. That said, I guess I will be buying oil from my dealership instead of using getting Mobil 1 as I had planned. Any comments on this? 