This chemist writes a very interesting and informative paper on gasoline brands, octane and additives. I was unpleasantly surprised about using the same brand of gasoline because of the deposits that are left from that brands additive package. Gonna try his suggestion about switching brands every 5k. If the following site has been linked to before, my humble apologies.
A chemists view on gasoline brands, octane and additives.
A chemists view on gasoline brands, octane and additives.