The best oil I`ve ever used! Conventional oils make my car feel like it`s being held back. Won`t rev smoothly or responsively. Mobil 1 15W50 makes it lightning fast responsive. Plus,it doesn`t turn to water when it gets hot,like conventionals. Yeah,synth blends aren`t even worth your time. The best conventional I`ve ever used was Valvoline All Climate. The worst oil I`ve ever used was Castrol Syntec. That stuff gave me very bad lifter tick and piston slap. Plus,it`s not a real synthetic.