> Regular, 87 octane.  When I drive out west at higher
> altitudes, and regular is lower octane because of the lower
> oxygen pp, I use mid-grade, but I probably don't need to.

There is a reason that "regular" is 87 below some elevation
(like 4500') and 85 above.  Because the gov't is making the
oil companies screw up your engine!

Seriously, "regular" is right for AC and waterboxer Vanagons,
high or low.  If you filled up in Denver and trucked your
Vanagon to Corpus Christi, it might be rough until you filled
up there.  Who does that?  Show of hands....

See: http://www.eia.doe.gov/glossary/glossary_g.htm
under "gasoline grades."

Richard