Probably going to get some heat for this but...
I have tried Mobil1 in my P5 (at a cost of $28 CAD + tax), and did not feel there was a difference, and after having used Castrol GTX in every vehicle I have owned with good results, I decided to try the Castrol Syntec Blend... it seems to work great, at a price I can afford to change every 5,000kms. So I will be sticking with that.
