I have an 05 5 speed Vibe/Corolla with around 51k miles(bought new) (original clutch). In the 4.5 years I have had the car I have used the Specialty Formulations fluid, Amsoil and for the past couple of years the Castrol Syntorq. I think I like the Castrol the best and was thinking of putting in new fluid this fall. For those of you who have used more than one transmission fluid in such a car what do you like the best?