&> find backing for what my mechanic tells me:  Premium
gas is 'better' in
> that one can go farther on a tank of premium than on
a tank of regular
> and that one should be looking at costs per
kilometre/mile rather than
> cost/litre (gallon).  He also suggests that since
premium burns more
> slowly (I'll assume that this is correct) that there
is more of 'push' on
> the piston and less of a 'slap' therefore being
easier on the engine.

in my experience, tain't true at all. no difference in
the miles per tank on regular 87, regular 89 and
premium 91/92/93. with the six different brands i've
run for 146,000 miles in my 88 bus. in shorter miles,
on the 87 camper, 91 carat and 91 gl, same trend shows
up: no difference between the octanes or the brands.

now, remember, that's MY bus with MY driving
habits/style and in MY area/region using the gasolines
that are sold in that area/region. around town, there
are three fuel distributors who fix prices and sell to
each other ... it's not unusual to see the Amoco truck
filling up an Exxon station or the Shell truck filling
up a Chevron station.

anybody wants to see the tabulated data, lemme know and
i'll send it to you. :)