http://www.gmtruckcentral.com/articles/ ... study.html
an independant oil filter study... also has air filter study as well
oil study too...
http://www.xs11.com/xs11-info/tech-tips ... -oils.html
maybe a little biased...
http://www.amsoil.com/lit/g3115.pdf
Lucas Oil Gas Additive...
http://www.heathwood.org/ourprogram/SCJ ... /WoodA.pdf