what type of oil you put it in your LC? I have seen so many people using Royal Purple, Redline, Mobil One, Castrol Syntec extended life and so on... I heard it from somewhere that when your vehicle is used to mineral oil and if you switch to synthetic, it is prone to leakage since the viscosity is lower. How much the synthetic really benefits from mineral? If driving sub zero weather, what would you suggest putting in?