I personally go with Castrol Syntec (5w-30)or Mobil1 (5w-30)..i sometimes use 10w-30 but it feels different than 5w-30...5w-30 feels better for some reason..probably because its not as thick. Im trying out different types of oils..next type im planning to try is Royal Purple..expensive stuff but i heard it does a good job..Another weird thing is..when i use castrol syntec..i fully boost more often than with Mobil1..sounds weird right? i dont know the answer to that but thats what i see when i use these oils..