I run good old dyno juice. Forget the price of synthetic! Most of the time I get too bored with an engine and yank it out around the time an oil change is due anyway. I guess I'm a bit of an odd ball... But I treat my cars right, give them what they want! Same goes for women! TREAT WOMEN BETTER THAN YOUR CARS, and you will find a woman that lets you keep your cars and spend more money on the car than them. It's amazing how that works out!