I also saw the MythBusters show about the a/c vs. gas mileage. What
stuck in my mind about the "test" was that the people standing around
outside were wearing jackets! The results would have been a lot more
accurate if it had actually been in hot weather. The compressors on the
vehicles probably didn't even run 50% of the test. I do agree that the
a/c affects small engines a lot more than larger. I have a 94 Ford
Aspire that got about 40+ mpg on two 500 mile trips I took in it last
winter. I have not actually checked the mileage with the a/c, but it
seems to knock off about 5 mpg, both in town and on the highway.
Larry