[88Silver924S]

Here in Washington state I believe all gasoline is at least 10% ethanol with rare exception. Ethanol is less energy dense than gasoline so straight gasoline should get one better mileage. Does anyone know if the difference is significant? I usually get in the mid 20's of mixed driving upper 20's highway. My '88 924s has the higher compression "944" engine and uses the higher octane gas. Does anyone use "regular" gas in their 944/924s/951/etc? Do winter/summer blends change gas mileage?