Questions questions questions, better to ask first then to F up later I suppose. I've been scouring the internet for this answer and everyone has an opinion. So I wanted to ask here for a direct answer and also because Volcano is like my Vdub Mentor on these matters. I need to do an oil change this weekend and the oil in the engine now id Mobil 1 5W-30 full synthetic. Manual says 5W-40 or 5W-30. However, I've also seen 0W-40 reccomended quite a bit. I have some gift cards to Pep Boys and they have Mobil 1 5W-40 but it's advertised as oil for Turbo Diesels. It has petrol specs on the back though. Confusing. But cutting to the chase. If I want the most performance out of my engine, what kind of oil should I feed her? And is Mobil 1 better than Castrol? What about Penetosin or even Royal Purple? I need to be able to buy it in store though. So I'm SOL with a suggestion for Motul or Amsoil.