I am happy to report my Vanagon and I just survived 10 weeks in Mexico.   I
didn't see any Nova gas the whole time I was there.  Magna is the most common
and is available everywhere-- I belive it was 87 octane.  (Part way through
the trip I noticed that the sticker by my gas tank said only 90 octane and
above...oh well. )  I forget the name of the premium gas but I think it was
92 octane.  It is pretty common but isn't everywhere.  Sometimes a pump
marked premium (red colored pump as opposed to the green for Magna) really
dispenses the Magna.  Prices right now are 4.79 pesos/liter= about $2 a
gallon for Magna.

In a side note, the only problem I had with the van the whole trip was when
the rear tires were slashed with a knife by a group of 30 angry, drunk
villagers in the middle of the night who were convinced that I tried to
strangle and kidknap one of their children.  I guess that wasn't really the
van's fault though.  Be careful where you park.

Doug Demarest
Minneapolis, MN
86 Vanagon