The only proven formula is to put the following oil in your car:
2 quarts of 0W20 Mobil 1 Advanced Fuel Economy
2 quarts of 0W30 Amsoil Synthetic
1.9 quarts of 5w20 Mobil 1 Extended Performance
2 quart of 5w30 Shell Rotella T6
w/TRD Filter (since, as we all know, a standard Toyota filter will cause backflow causing the cam tower leak).
I have scientific data that proves if you don't do this your engine will explode when your engine hits exactly 783,211 miles (short life for a Toyota). This information was provided to me by the owner of Blackstone Lab's lab(rador). I was skeptical at first, but when the lab, which was grown in a lab, and had a lab coat gave me the data, I was convinced.