if i'm not mistaken (which is rare, but it does happen...) the reason for the lack of smoke in the worlds was due to lack of oil in the fuel....i know when i made the change from byrons race 30/11 to purple sidewinder (30/6? or 30/7? nobody has been able to tell me for sure...just don't use the sidewinder unless your motor is 99% completely broken in due to the lack of oil!!!) the smoke trail went from nice and smooth to almost non-existant...and i had to lean a couple hours on the bottom and 1 on the top of my B5....so there's ya another milage tip....a low oil fuel will yeild slightly better run times due to being able to lean it more...