AMzoil in all my cars. My toyota tacoma now has 309,000 on it and doesn't burn or leak a drop of oil. My gas mileage went up as well when I started using it. And I change my oil every 9000 miles instead of 3500. Hey if synthetic is good enough for the jets I fly I figure they can't be bad for your vehicle. Granted your RPMs in a car are only runninf 2300 on the highway and my jet is turning 37500 rpms LOL!