I have a heavily supped up pred 500. its time for an oil change but don't know what to use as far as weight and brand. the guy I bought it from told me to run nothing but amsoil in it because of all the mods. it runs on race fuel or 93 octane, and has everything in the motor aftermarket, built for speed. it runs pretty hot already, but I don't know what to use in it. Anybody with a built quad have reccomendations?