Hi, i dont know if this is old news but here's a link about a chemist's view on gas additives/brands, etc.
http://64.233.187.104/search?q=cach...fference+in+brands+of+gas+shell+chevron&hl=en
High
http://64.233.187.104/search?q=cach...fference+in+brands+of+gas+shell+chevron&hl=en
High