All the oils ive used in my car.. Supertech, Supertech Semi Syn, Supertech SYn, Shell Conventional, Castrol Synthetic, Mobil 1 all proved to be good oils for my car. My next choice of oil will be 50% Valvoline Conv. and 50% Valvoline Maxlife Synthetic. I want a oil that will quiet my valvetrain because of Hyundai's crappy Lifter noise. I've heard that some oils work for making them quieter.. which oils made your valves quieter?